X-ray Structure and Molecular-Packing Analysis of l'-(p-Bromophenyl)-3'-ethyl- 1 ',3 ',4',5 '-tetrahy dro- 1,2-dideo xy-D-glycero-ot-D-galacto-heptofuranoso[ 2, l-d]imidazole- 2'-thione Monohydrate

1658 5'-O-ACETYL-6,3'-ANHYDRO-2'-DEOXY-6-METHYL- 1- l-D-XY LOFURANOSYLURACIL a oms as ound in some cyclonucleosides (B ennan & Sunda alingham, 1973; Yamaga a, Koshibe, Tokuoka, Fujii, Fujiwa a, Kanai & Tomi a, 1979; Yamaga a, Suzuki, Fujii, Fujiwa a & Tomi a, 1979). The bond dis ances and angles in he u acil moie y a e in good ag eemen wi h s anda d alues (Taylo & Kenna d, 1982). Howe e , in he u anose ing, he C(1')-C(2')-C(3') angle [98.5 (4) °] is signi ican ly smalle han he a e age alue (101.3 °) o he no mal u anose ings (Sunda alingam, 1973), and i is p ob- ably due o he E 2 suga pucke ing s ained by cycliza ion. Indeed, his alue ag ees well wi h he sugges ed one om he co ela ion be ween he endocyclic bond angles and he pseudo o a ional pa ame e s (Wes ho & Sunda alingam, 1980). In he p esen c ys al no base s acking is obse ed. One hyd ogen bond, i.e. N(3)--H...0(4) [2.834 (5) A], is ound be ween he adjacen molecules ela ed by wo old sc ew symme y o o m an in ini e hyd ogen- bonded column along he b axis. Re e ences ABRAHAM, R. L. & MCLAUCHLAM, K. M. (1962). Mol. Phys. 5, 513-523. BRENNAN, Y. & SUNDARALINGAM, M. (1973). Biochem. Biophys. Res. Commun. 52, 13-16. In e na ional Tables o X- ay C ys allog aphy (1974). Vol. IV, pp. 72-75. Bi mingham: Kynoch P ess. (P esen dis ibu o D. Reidel, Do d ech .) JOHNSON, C. K. (1976). ORTEPII. Repo ORNL-5138. Oak Ridge Na ional Labo a o y, Tennessee. SUNDARALINGAM, M. (1973). Je usalem Sy up. Quan um Chem. Biochem. 5, 417-456. TAYLOR, R. & KENNARD, O. (1982). J. Am. Chem. Soc. 104, 3209-3212. UEDA, T. & SHUTO, S. (1984). Nucleosides Nucleo ides, 3, 295-302. UEOA, T., SHUTO, S., SANO, T., USUI, H. & INOUE, H. (1982). Nucleic Acids Res. Sy up. Se . 11, 5-8. UEDA, T., USUI, H., SHUTO, S. ~g, INOUE, H. (1984). Chem. Pha m. Bull. 32, 3410-3416. UNICS (1979). The Uni e sal C ys allog aphic Compu ing Sys em-Osaka. Lib a y o P og ams, Compu a ion Cen e , Osaka Uni . WESTHOF, E. ~g, SUNDARALINGAM, M. (1980). J. Am. Chem, Soc. 102, 1493-1499. YAMAGATA, Y., KOSHIBE, M., TOKUOKA, R., FUJI1, S., FUJIWARA, T., KANAI, T. & TOMITA, K. (1979). Ac a C ys . B35, 382-389. YAMAGATA, Y., OKABE, N., TOMITA, K., SHUTO, S., INOUE, H. & UEDA, T. (1985). Ac a C ys . C41, 1653-1656. YAMAGATA, Y., SUZUKI, Y., FUJIl, S., FUJIWARA, T. ~. TOMITA, K. (1979). Ac a C ys . B35, 1136-1140. YONEDA, M., TANAKA, K., FUJIWARA, T. & TOMITA, K. (1979). Ac a C ys . B35, 2355-2358. Ac a C ys . (1985). C41, 1658-1662 X- ay S uc u e and Molecula -Packing Analysis o l'-(p-B omophenyl)-3'-e hyl- 1 ',3 ',4',5 '- e ahy d o- 1,2-dideo xy-D-glyce o-o -D-galac o-hep o u anoso[ 2, l-d]imidazole- 2'- hione Monohyd a e BY C. F. CONDE, M. MILLAN, A. CONDE AND R. M.A, RQUEZ Depa amen o de Op ica y Seccidn de F[sica del Cen o Coo dinado del CSIC, Uni e sidad de Se illa, Spain (Recei ed 25 Feb ua y 1985; accep ed 10 June 1985) Abs ac . 6- (p-B omophenyl)-4-e hyl-3-hyd oxy-2- (1,2,3- ihyd oxyp opyl)-2,3,3 a,5,6,6 a-hexahyd o u o- [2,3-d]imidazole-5(4H)- hione monohyd a e, C16H21- B N2OsS.H20, M ----451.3, o ho hombic, P21212 l, a = 6.073 (3), b = 15.977 (8), c = 19.213 (9) A, V= 1864 (2) A 3, Z = 4, D m = 1.62 (1), D x-- 1.61 Mg m -a, 2(Mo Ka) = 0.7107 A, g= 2.32 mm -1, F(000) = 928, oom empe a u e, inal R = 0.080 o 2147 obse ed e lexions. The suga ing adop s he 4E con o ma ion and he dihed al angle in he bicyclic sys em is 115.0 (3) °. A h ee-dimensional ne wo k o hyd ogen bonds links he molecules o s abilize he c ys al s uc u e. The la ice ene gy was compu ed in he a om-a om app oach using an de Waals po en ial unc ions. These calcula ions accoun sa is ac o ily o 0108-2701/85/111658-05501.50 all he ea u es o he c ys al packing, including o a ion abou selec ed bonds in he molecule. In oduc ion. The c ys al s uc u e de e mina ion o he i le compound (I) was unde aken as pa o a con inuing esea ch p ojec in his labo a o y in ol ing glucimidazoles and imidazole C-nucleosides. Some o hese compounds, p epa ed in he O ganic Chemis y Depa men o he Uni e si y o Ex emadu a, ha e been s udied (e.g. Es ada, Conde & M~. quez, 1983, 1984; Conde, Millan, Conde & M~ quez, 1985) in o de o es ablish he con o ma ional de ails o he molecule in he solid s a e. The applica ion o amino- ni ile syn hesis o he p epa a ion o he new 2-e hylamino-2-deoxyhep ose ha ing he D-glyce o-D- © 1985 In e na ional Union o C ys allog aphy C. F. CONDE, M. MILLAN, A. CONDE AND R. M/~,RQUEZ galac o con igu a ion and i s eac ion wi h 4-b omo- phenyl iso hiocyana e o a o d he i le compound has been ecen ly epo ed (Galbis P6 ez, Palacios Alba - ~,n, Jim6nez Requejo & A alos Gonz~es, 1984). I s chemical na u e was es ablished om elemen al analysis and spec oscopic IR and ~H NMR da a. H ~. ~,~ i'OH /0~ CsH4e HOCH2 /~ ~N,~S OH H H ~ C2H5 (I) .H20 Expe imen al. Single c ys als in he o m o colou less needles elonga ed along [100]. D m by lo a ion me hod. C ys al 0.37 × 0.17 x 0.08 mm. Uni -cell pa ame e s by leas squa es om 25 e lexions, 6 < 0< 20 ° . En a -Nonius CAD-4 di ac ome e , g aphi e mono- ch oma o , 20 < 60 ° (0 < h _< 8, 0 < k < 22, 0 <I _< 27), 09-20 scan mode. Two s anda d e lexions (121, 113), a ia ion in in ensi y less han 3% o he mean alue. 3093 independen e lexions measu ed, 946 conside ed unobse ed [I < 20(/)]. Lo en z and pola iza ion co ec ion; no co ec ion o abso p ion (/d~ ~0.15) o ex inc ion. Pa e son unc ion and hea y- a om me hod wi h he ini ial se o phases based on B - and S-a om posi ions. Full-ma ix leas -squa es e ine- men on F, aniso opic; di e ence Fou ie syn hesis e ela ed he H-a om posi ions; iso opic empe a u e ac o o each H a om equal o ha o he a om bonded o i ; u he leas -squa es e inemen including he posi ional pa ame e s o he H a oms and anomalous-dispe sion co ec ion o B and S a omic sca e ing ac o s (In e na ional Tables o X- ay C ys allog aphy, 1974) educed wR o 0.082 (R = 0.080); weigh ing scheme based on he s a is ical coun c i e ion (w = lla2). (A/6)max = 0.03, S = 0.80 o 305 e ined pa ame e s. No. o e lexions/No, o pa ame e s = 7.04. Final di e ence syn hesis showed 0.35 > Ap > -0.40 e ,~-3. The enan iomo phic o m o he molecule was e ined sepa a ely and con e ged o a inal wR alue o 0.085 (R = 0.083). The applica ion o he ,~ es (Hamil on, 1965) indica ed ha he i s enan iomo ph is co ec a a signi icance le el much lowe han 0.005 [wR(2)/wR(1)= 1.036; ~i,1842,0.005~--1.002] and, he e o e, can be e ained as he s uc u al chi ali y. Mo eo e , his con igu a ion is consis en wi h ha de ined by e e ence o he suga moie y (Galbis P6 ez e al., 1984). C ys allog aphic p og ams o he XRA Y70 sys em (S ewa , Kundell & Baldwin, 1970) we e used h oughou . Diseusslon. F ac ional a omic coo dina es and equi a- len iso opic empe a u e ac o s (Hamil on, 1959) o 1659 non-hyd ogen a oms a e lis ed in Table 1.* A om numbe ing and bond leng hs and angles in ol ing non-hyd ogen a oms a e gi en in Fig. 1. * Lis s o s uc u e ac o s, aniso opic he mal pa ame e s and H-a om pa ame e s ha e been deposi ed wi h he B i ish Lib a y Lending Di ision as Supplemen a y Publica ion No. SUP 42295 (16 pp.). Copies may be ob ained h ough The Execu i e Sec e a y, In e na ional Union o C ys allog aphy, 5 Abbey Squa e, Ches e CH 1 2HU, England. Table 1. A omic ac ional coo dina es and equi alen iso opic empe a u e ac o s (A 2 x 103) Ueq = ~ Z ~.jUi l* a* ai.ajcos(a .aj). x y z Ueq B 0-8503 (2) 0.61690 (8) 0.46738 (6) 636 (4) S 0.7612 (3) 0.72967 (12) 0.81323 (11) 351 (5) O(1) 1-2747 (9) 0.9150 (3) 0.6973 (3) 292 (13) 0(2) 1.4766 (10) 1.0111 (4) 0.8260 (3) 380 (16) 0(3) 0-8305 (10) 0.9509 (4) 0.7481 (3) 368 (16) 0(4) 1.1017 (17) 1.0615 (4) 0.6047 (3) 364 (16) 0(5) 0.6331 (15) 1.0684 (7) 0.5642 (4) 67 (3) 0(6) 0.0442 (17) 0.5290 (8) 0.0372 (4) 73 (3) N(1) 1.1076 (10) 0.7883 (4) 0.7380 (3) 317 (17) N(2) 1.0924 (10) 0.8360 (4) 0.8450 (3) 278 (16) C(I) 0.9915 (11) 0.7865 (4) 0.7992 (4) 274 (17) C(2) 1-2935 (11) 0.8455 (5) 0.7412 (4) 282 (18) C(3) 1.2864 (11) 0.8767 (5) 0.8176 (3) 293 (17) C(4) 1-2677(11) 0.9731 (5) 0.8116(3) 282(17) C(5) 1-2120(11) 0.9895 (4) 0.7350(3) 253 (17) C(6) 0.9766 (12) 1-0127 (5) 0-7203 (4) 290 (18) C(7) 0.9287 (13) 1-0225 (4) 0-6427 (4) 282 (18) C(8) 0-7121 (14) 1-0681 (9) 0-6327 (5) 52 (3) C(9) 1.0459 (14) 0.7464 (4) 0-6754 (3) 299 (19) C(10) 0.8519 (15) 0.7669 (6) 0.6425 (5) 42 (2) C(11) 0.7917 (15) 0.7272 (7) 0.5799 (5) 43 (5) C(12) 0-9286 (16) 0.6668 (5) 0.5538 (4) 38 (2) C(13) 1.1336 (18) 0.6482 (6) 0.5854 (5) 45 (3) C(14) 1.1881 (14) 0.6872 (5) 0.6472 (5) 38 (2) C(15) 1.0334 (15) 0-8439 (6) 0.9193 (4) 37 (2) C(16) 1.1796 (18) 0-7924 (6) 0.9641 (5) 47 (3) ~,~S~ C(16) C(15~ ~1 ".o 0(2) 'dbo °--.~ago ~ ~,Y ,-!., "~,,.~ : <~ ~-~ . ~/ % -~ S C(13~119.0 _ 120~)~(10) 0 < 4 ,i ....-"Lz7";""- ~ - "IY > B Pig. I. Bond leng hs (A) and angles (o). (S anda d de ia ions a e in he anges 0.02-0.05 i and 1.7-3-1 o, espec i ely.) 1660 C 16H21B N2OsS.H20 Molecula geome y Bond dis ances and angles in he imidazolidine ing ag ee wi h he mean alues epo ed o analogous glyco u anoimidazolidine-2- hione compounds (Es ada, Conde & M i quez, 1983, 1984; Conde, Millan, Conde & M/u'quez, 1985). The S-C bond leng h o 1.690 (7)A and hose obse ed o N(1)-- C(1)= 1.371 (9) and N(2)-C(1) = 1-333 (9) A should indica e he con ibu ion o he canonical esonance o ms o he hiou ea sys em: I I I / N -- -//N+-- -- C / N S ~- C -S--C~. -S ~N-- N~ %N+..__._ L I I (a) (b) (c) The obse ed asymme y o he endocyclic N-C bonds (A/ = 4.2) is due o he di e en subs i uen s a he wo N a oms. The imidazolidine ing is no plana : he ing a oms de ia e signi ican ly om he leas -squa es plane [Y(A/ )2= 19.06; X 2 a 95% = 5.991 and he pucke ing ampli ude (C eme & Pople, 1975) is Q=0.032(8)A. This ea u e was also ound in analogous s uc u es (Es ada, Conde & M i quez, 1983; Conde, Millan, Conde & M i quez, 1985). The phenyl ing shows a s a is ically signi ican de ia ion om plana i y [~(A/a) z = 18.98; ,Z 2 a 95% = 7.811 and o ms a dihed al angle o 64.4 (2) ° wi h he imidazolidine ing. Values o his dihed al angle in he ange 45-80 ° we e ound o analogous compounds, and should indica e a signi ican con i- bu ion o in amolecula po en ial ene gy (phenyl- imidazolidine) o e he in e molecula one. The e hyl g oup is also wis ed wi h espec o he imidazolidine ing as indica ed by he o sion angle C(1)-N(2)-C(15)-C(16) = 98.9 (9) °. Bond leng hs and angles in he u anosyl ing a e close o he mean alues obse ed o analogous compounds. The obse ed asymme y o he endocyclic bonds O(1)-C(2)= 1.400 (9) and O(1)-C(5)= 1.444 (8)A (A/a= 3.65) is a ypical ea u e o hese compounds due o anome ic e ec s. The u anose ing is no plana as expec ed. In e ms o he ing-pucke ing coo dina es (C eme & Pople, 1975) he ampli ude and phase magni udes a e Q=0.188 (6) A and ~0= -42 (2) ° o he sequence O(1)-C(2)-C(3)-C(4)- C(5) and he esul ing con o ma ion co esponds o he pucke ing mode 4E, simila o ha ound o o he analogous compounds (Conde, L pez-Cas o & M/~ - quez, 1978; Es ada, Conde & M~. quez, 1984) bu i is di e en om ha ound in ano he ecen ly epo ed s uc u e (Conde, Millan, Conde & Mh quez, 1985). The asymme y pa ame e o Na delli (1983a), ACs[C(5)] =0.014 (3), indica es app oxima e mi o - plane symme y in he ing. The small alue o he o sion angle O(1)-C(2)-C(3)-C(4) [-1.5 (7)°], a ypical ea u e o hese compounds, may be a ibu ed o he dis o ion o he u anose g oup on i s usion wi h he imidazolidine ing. The wo used ings in he bicyclic sys em show a cis o m o coupling and he bonds a C(2) and C(3) a oms a e nea ly eclipsed, hese ea u es being simila o hose obse ed o analogous compounds. The dihed al angle be ween he leas -squa es planes h ough he imidazoli- dine and u anose ings is 115.0 (3) °. C ys al-packing analysis Fig. 2 shows he con en s o he uni cell iewed down [100]. The c ys al s uc u e is s abilized by a h ee-dimensional hyd ogen-bonding ne wo k. Molecules a e linked o o m chains pa allel o [ 100]. In hese chains each molecule is linked o ha ela ed by a cell ansla ion by O(3)--H(O3)---O(2)(x--1, y, z). Also, each molecule is linked o he neighbou ela ed by a wo old sc ew axis pa allel o [100l by 0(5)- H(O5)..-B (x -), -y+~, --z+l). Also, molecules a e linked o o m chains pa allel o 1001] by wo O-H...O hyd ogen bonds in ol ing he hyd a ion wa e molecule: O(6)-H(O61)-..O(4)(-x+l, y ~, -z+½). Finally, he con ac O(4)-H(O4)-..S(-x+2, y+½, -z+-}) be ween molecules ela ed by a sc ew axis along 1010] could be conside ed a hyd ogen bond. De ails o he geome y o hese hyd ogen bonds a e gi en in Table 2. Fo he O-H...O con ac s lis ed in Table 2 he alues o he pa ame e d, de ined as he di e ence be ween he sum o he an de Waals adii o H and O (1.20 and 1.50 A) and he in e a omic dis ance (Taylo & Kenna d, 1982), a e 0.89 and 0.61 A espec i ely, sa is ying he ule d > 0.3 A, and he angles O-H...O 1 1 14 2" 0- 14 14 L L ..... 14 C .,.~. 14 --0 "~ Fig. 2. A iew o he uni -cell con en s along [ 1001. C. F. CONDE, M. MILLAN, A. CONDE AND R. MARQUEZ 1661 Table 2. Geome y o he possible hyd ogen bonds X-H...Y X...Y(A) X-H (A) H...Y(A) X-H...Y(°) O(5)-H(O5)...B ~ 3.476 (I l) 0.84 (23) 2.68 (23) 160 (22) O(3)-H(O3)...O(2 n) 2.790 (9) 1.00 (16) 1.82 (16) 163 (14) O(6)-H(O61)...O(4 H~) 2.913 (10) 0.87 (25) 2.09 (25) 159 (23) O(4)-H(O4)...S ~ 3.225 (7) 0.67 (14) 2.64 (15) 148 (16) Symme y code: (i)x-½,--y+~,--z+l; (ii)x--l, y, z; (iii)-x+l, y----~, -z+½; (i )-x+2,Y+½,-z+½. can be compa ed wi h he mean alue o 165.8 (12) ° o bonds wi h O...H > 1.81 A (Allen, Kenna d & Taylo , 1983). The sho O-H...B con ac has d> 0.3 A and angle O--H...B = 160 (22) ° and so can be conside ed as a hyd ogen bond. Finally, he p esence o sho con ac s in ol ing he S a om and ha ing hyd ogen-bond cha ac e is ics is a ea u e obse ed in o he analogous compounds. No o he in e molecula con ac signi ican ly sho e han he sum o he an de Waals adii has been de ec ed. The molecula geome y and c ys al packing we e com- pu ed by PARST (Na delli, 1983b). A minimiza ion o he c ys al la ice ene gy wi h espec o la ice cons an s, molecula ansla ion and o a ion and also sub o a ion o molecula agmen s abou selec ed bonds as axes was pe o med by means o he p og am PCK6 (Williams, 1972b, 1974) s a ing om he expe imen al s uc u e. Po en ial unc ions in he o m U( )=-A -6+ B exp(-C ) we e used o ep esen he non-bonded in e a omic po en ial ene gy. The se o po en ial pa ame e s included pa ame e s i ed by Williams (1972a) o he C...C and H---H in e ac ions, by Go e s (1975) o N...N, by Mason & K ee oy (1955) o O...O and S...S and pa ame e s o Bu gos & Bonadeo (1977) o B ...B . Fo mixed in e ac ions he combina ion ules o Mi skaya (1973) we e used. Fou uns o ene gy minimiza ion we e ca ied ou om wo igid bodies: he gluco u anoimidazolidine and he hyd a ion wa e molecules, espec i ely; in he i s , he X- ay molecula s uc u e was e ained and he la ice cons an s we e ixed; in he second, cell pa ame e s we e included as a iables; in he hi d, he phenyl ing, he e hyl g oup and he suga chain o a ions we e elaxed; cell pa ame e s we e also included as a iables in he las un. Rep esen a i e esul s o ene gy-minimiza ion uns a e gi en in Table 3. The calcula ed alues o la ice ene gy, no included in Table 3, a e highe han he eal ones because he in e molecula hyd ogen bonds we e ea ed by an de Waals po en ial unc ions. As shown in Table 3, he inclusion o cell pa ame e s as a iables leads o a signi ican (~3%) expansion o he cell along a and a mino expansion (~0.4%) along e, while a con ac ion (~5%) esul s along b. This unexpec ed expansion o he cell may be a ibu ed o he app oach used in which he hyd ogen-bond con ac s a e ep esen ed by an de Waals po en ial unc ions. Table 3. Molecula -packing analysis (a) (b) (c) (cO Cell pa ame e s a (A) 6.073 (3)* 6-229 6.073* 6.237 b (A) 15.977 (8)* 15.897 15-977" 15.932 c(A) 19.213(9)* 19-284 19.213" 19.301 Gluco u ano-imidazolidine molecule T ansla ion (A) 0.15 0. I0 0.13 0.09 Ro a ion (o) 7.0 6.8 5.9 6.0 Sub o a ions (o) C(2)-N(I)-C(9)-C(10) -111.4(9)* -111.4" -113.6 -113.6 C(I)-N(2)-C(I 5)-C(16) 98.9 (9)* 98.9* 95.6 95.0 O(I)-C(5)-C(6)-C(7) -54.9 (8)* -54.9* -64.4 -63.5 Hyd a ion wa e molecule T ansla ion (A) 0-09 0-06 0.07 0.05 Ro a ion (o) 2.2 1.9 1.9 2-0 (a) Wi h cell pa ame e s and o ques ixed a expe imen al alues (*); (b) wi h op imized cell pa ame e s and o ques ixed; (c) wi h cell pa ame e s ixed and o ques elaxed; (cO wi h op imized cell pa ame e s and o ques. So, a highe con ibu ion o he epulsi e e m o hese con ac s esul s and he con ac s a e expanded. As shown in Table 2, hyd ogen-bond chains occu mainly along [100] and also along [001]. Apa om his, he heo e ical con igu a ion ag ees well wi h he expe i- men al s uc u e, in spi e o he exis ence o a hyd a- ion wa e molecule which links he neighbou ing gluco- u anoimidazolidine molecules ia O-H...O hyd ogen bonds. All he op imized s uc u es emain e y simila wi h ega d o he molecula pa ame e s and he o ques o he selec ed sub o a ions. As shown in Table 3, shi s o posi ional and o ien a ional molecula pa ame e s a e lowe han 0.15 A and 7 ° espec i ely. To sional angles o selec ed molecula agmen s a e ep oduced wi hin 2 ° o he e hyl and b omophenyl g oups. The highe dis o ion which is obse ed o he suga chain may be a ibu ed o he p esence o he in e molecula hyd ogen bonds in ol ing a oms in he chain. The au ho s hank P o esso J. A. Galbis P+ ez o supplying he c ys als and o help ul discussions on chemical aspec s and P o esso A. Ldpez-Cas o o collec ing he di ac ome e da a. The p esen wo k is pa o a esea ch p ojec suppo ed by a g an om he CAICYT o he Spanish Go e nmen . Re e ences ALLEN, F. H., KENNARD, O. & TAYLOR, R. (1983). Acc. Chem. Res. 16, 146-153. BURGOS, E. & BONADEO, H. (1977). Chem. Phys. Le . 49, 475-478. CONDE, A., LOPEZ-CASTRO, A. • MARQUEZ, R. (1978). Re . Ibe oam. C is . Mine . Me alogen. 1(I), 23-36. CONDE, C. F., MILLAN, M., CONDE, A. & M.~RQUEZ, R. (1985). Ac a C ys . C41, 277-280. CREMER, D. & POPLE, J. A. (1975). J. Am. Chem. Soc. 97, 1354-1358. 1662 CI6H2IB N2OsS.H20 ESTRADA, M. D., CONDE, A. & MA.RQUEZ, R. (1983). Ac a C ys . C39, 1418-1421. ESTRADA, M. D., CONDE, A. & M.~RQUEZ, R. (1984). Ac a C ys . C40, 898-901. GALmS PI~REZ, J. A., PALACIOS ALBARRAN, J. C., JIMI~NEZ REQUEJO, J. L. & AVALOS GONZ.~LES, M. (1984). Ca bohyd . Res. 129, 131-142. GOVERS, H. A. J. (1975). Ac a C ys . A31, 380-385. HAMILTON, W. C. (1959). Ac a C ys . 12, 609-610. HAMILTON, W. C. (1965). Ac a C ys . 18, 502-510. In e na ional Tables o X- ay C ys allog aphy (1974). Vol. IV. Bi mingham: Kynoch P ess. (P esen dis ibu o D. Reidel, Do d ech .) MASON, E. A. & KREEVOY, M. M. (1955). J. Am. Chem. Soc. 77, 5808-5814. MIRSKAYA, K. V. (1973). Te ahed on, 29, 679-682. NARDELLI, M. (1983a). Ac a C ys . C39, 1141-1142. NARDELLI, M. (1983b). Compu . Chem. 7, 95-98. STEWART, J. M., KUNDELL, F. A. & BALDWIN, J. C. (1970). The XRA WIO sys em. Compu e Science Cen e , Uni . o Ma yland, College Pa k, Ma yland. TAYLOR, R. & KENNARD, O. (1982). J. Am. Chem. Soc. 104, 5063-5070. WILLIAMS, D. E. (1972a). Ac a C ys . A28, 84-88. WILLIAMS, D. E. (1972b). Ac a C ys . A28, 629-635. WILLIAMS, D. E. (1974). Ac a C ys . A30, 71-77. Ac a C ys . (1985). C41, 1662-1664 S uc u e o 1,2,4,5,6,7,8,9-Oc achlo o- 10,10-dime hoxy ieyelo[5.2.1.02,6]deca-4,8-dien - 3-one BY N. GALEgI~: 'Rudje Bo'~ko id' Ins i u e, PO Box 1016, 41 O01 Zag eb, Yugosla ia I. MATIJASIC Labo a o y o O ganic Chemis y and Biochemis y, Facul y o Science, Uni e si y o Zag eb, S ossmaye o g 14, 41000 Zag eb, Yugosla ia AND M. BRUVO Labo a o y o Gene al and Ino ganic Chemis y, Facul y o Science, Uni e si y o Zag eb, ul. Soc. e olucije 8, 41000 Zag eb, Yugosla ia (Recei ed 29 Ap il 1985; accep ed 11 June 1985) Abs ac . C12H6C1803, M =481.80 , monoclinic, P21/c , a=11.028(9), b=11.871(3), c=13.231(9)A, = 93.14 (3) °, V= 1730 (2) A 3, Z = 4, Dx= 1.850 Mg m -3, 2(Mo Ka) -- 0.7107/k,/~ = 1.32 mm -1, F(000) = 952, T= 293 K, inal R = 0.035 o 3518 obse ed e lec ions. The C(sp3)--C1 and C(sp2)-Cl bond-leng h anges a e 1.744 (2)--1.767 (2) and 1.688 (2)-1.696 (2),/k, espec i ely. The C(sp3) - C(sp 3) bond leng hs a e somewha ex ended and ange om 1.572 (3) o 1.585 (3)/~. The b idgehead C-C-C and O-C-O angles a e 91.6(1) and 114.6 (2) °, espec i ely, while he O-C-O-C o sion angles a e -53.5 (2) and -47.6 (3) ° . The i e- membe ed ing adjacen o he no bo nene ing sys em is in he endo con igu a ion wi h espec o i . In oduc ion. In he cycloaddi ion eac ion be ween 1,2,3,4- e achlo o-5,5-dime hoxycyclopen adiene wi h dime hyl dib omomaleic es e he p oduc was no dime hyl 5,6-dib omo- 1,2,3,4- e achlo o-7,7-dime- hoxybicyclo[2.2.1]hep -2-ene-5,6-dica boxyla e (Van- ~ik, Sunko & Lo i6, 1985) as expec ed. The X- ay s uc u e de e mina ion showed ha he esul o he eac ion was a pa ially hyd olyzed dime o he cyclopen adiene de i a i e. The s uc u e de e mina ion was unde aken o gi e addi ional in o ma ion on his in e es ing s ained molecule. Expe imen al. In ensi y da a collec ed om a c ys al 0.25 × 0.34 x 0.42 mm wi h c ys al aces +(110), +(001), +(il 1), +(liD. Philips PW 1100 ou -ci cle di ac ome e , 0--20 scanning echnique, scan wid h 1.80 °, scan a e 0.06 s -1. Uni -cell pa ame e s ob- ained om leas -squa es analysis o 16 e lec ions wi h 20 alues anging om 12 o 20 ° . Absen e lec ions hOl, l ~ 2n and 0k0, k 4: 2n con i med space g oup P21/c. Ou o 4362 e lec ions scanned wi hin a quad an +h,k,l (h +15, k 16, l 18), up o sin0/2 <0.70A -1, 4166 unique e lec ions classi ied as obse ed. Th ee s anda d e lec ions (312, 106, 060) measu ed e e y 2 h showed an a e aged a ia ion o 1.0 (1)%. Co ec ions applied o Lo en z and pola iza ion e ec s. No co ec ion o abso p ion o ex inc ion. S uc u e sol ed by di ec me hods 0108-2701/85/I 11662-03501.50 © 1985 In e na ional Union o C ys allog aphy