Structures of four trans-2-hydroxy- and methoxy-2-methyl-3,4-dihydro-4-alkyl-2H,5H-pyrano[3,2-c][1]benzopyran-5-ones

Autor: Verner Schomaker, Edward J. Valente, Drake S. Eggleston
Rok vydání: 1987
Předmět:
Zdroj: Acta Crystallographica Section C Crystal Structure Communications. 43:533-536
ISSN: 0108-2701
DOI: 10.1107/s0108270187095131
Popis: Derivatives of 2-methyl-3,4-dihydro-2H,5Hpyrano[ 3,2-c)[ l)benzopyran-5-one. ( l) Racemic trans2-methoxy-4-(2-propyl), Mr= 288·3, monoclinic, P2ifc, a= 13· 737 (3), b = 13·228 (6), c = l7·229(4)A, P=l02·93(2) 0 , V=3051·4A3, Z=8 (two molecules/asymmetric unit), Dx = 1 ·255 g cm3, )..(Mo Ka) = O· 71073 A, μ = 0·908 cm· , F(OOO) = 1232, T = 298 K, final R = 0·050 for 3988 unique intensities. Dihydropyran rings in C 17H 200 4 are halfchairs, one being distorted toward the d,e-diplanar form. (2) Resolved trans-2-methoxy-4-cyclohexyl, Mr = 328-4, orthorhombic, ni2121, a = 10·468 (5), b = 11·245 (5). C = 14·465 (4)A, V= 1702·7 A3, Z=4, Dx= 1·281 g cm3, A.(MoKa) = 0·71073 A, μ = 0·823 cm, F(OOO) = 704, T = 298 K, final R = 0·051 for 2481 unique intensities. Compound, C 20H240 4 , spontaneously resolves on crystallization from methanol:acetone; data specimen determined to be 2R,4R by circular dichroism spectrum and comparison with structures of known configuration. Dihydropyran ring has a d,e-diplanar conformation. (3) Racemic trans2-hydroxy-4-(2-propyl). Compound crystallizes as the hemihydrate C 16H 180 4.!H10; Mr= 283-3, triclinic, PI, a = 9·015 (4), b = 10·216 (4), c = 16·208 (5) A, «= 103·08 (3), P= 95·42 (3), Y= 95·28 (3) , V = 1437 ·6 A 3, Z = 4 (two molecules/asymmetric unit), Dx = 1·309 g cm-, A.(Mo Ka)= O· 71073 A, μ = 0· 890 cm, F(OOO) = 604, T = 298 K, final R = 0· 040 for 4656 unique reflections. One dihydropyran ring is a half-chair, the other has an e/-diplanar conformation. Intermolecular hydrogen bonding occurs between the water and the hydroxyls and lactone carbonyls of each coumarin with Q ... Q distances between 2·82 and 2-90 A. (4) Racemic trans-2-hydroxyl-4-(2-propyl) derivative also cocrystallizes with 4-hydroxy-2H-benzopyran-2-one (1:1), M,=436·4, triclinic, PI, a = 8·669 (2), b = 10·506 (4), c = 12.559 (2) A, a = 0108-2701/87 /0305 3 3-04$0 1.50 102·98 (2), f3= 107·56 (2), /= 93 ·63 (2) , V= 1052·0A3, Z=2, Dx=l·378gcm-3, ..l.(Mo Ka)= 0·71073 A,μ= 0·941 cm1, F(OOO) = 460, T= 298 K, final R = 0·041 for 3322 unique reflections. Cocrystalline C 16H180 4.C9H60 3 shows chains of H bonds linking the hydroxyls of the coumarins alternately with the lactone carbonyls, O· · ·O distances 2·68 and 2·75 A. The dihydropyran ring has a half-chair conformation. Introduction. Analogs of the clinically useful oral anticoagulant drug warfarin, with alkyl substituents in place of the side-chain phenyl group, can be prepared by Michael-type addition of a,,li-unsaturated methyl ketones with 4-hydroxycoumarin. Products invariably crystallize as one of the cyclic diastereomeric hemiketals but in solution the open-chain keto form generally predominates. Methyl ketals can be made by treatment of the hemiketal/keto mixture with acidic methanol. Structures of 4-alkyl-2-hydroxyand methoxy-2-methyl-3,4
Databáze: OpenAIRE
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