Lyle W. Spruce

The structure of methyl 2-chloro-8-oxo-6H,8H-[1]benzopyrano[4',3':4,5]imidazo[2,1-b][1,3]thiazine-10-carboxylate

C 15HgC1N204S, M r = 348.76, orthorhombic, Pbca, a = 7.1732 (6), b = 13.872 (1), c = * To whom all correspondence should be addressed. 0108-2701/87/091723-04501.50 28.627 (2) A, V = 2848.6 (4) A 3, Z = 8, Dx= 1.627gcm -3, CuKfi, 2 = 1 . 5 4 1 8 A , p = 3 8 . 0 c m -1, F(000) -1424, T = 298 K, R = 0.049 for 2913 reflections. The molecule consists of a chlorophenyl, a pyran,

STEREOCHEMICAL AND A SINGLE-CRYSTAL X-RAY DIFFRACTION ANALYSIS OF 2,3,4,4a,6,10b-HEXAHYDRO-6-PHENYL-1,4-METHANO-1H-DIBENZO[b,d]THIOPYRAN: THE ADDITION PRODUCT FROM THE REACTION OF DIPHENYL THIONE AND NORBORNENE

Abstract The adduct obtained from the reaction of diphenyl thione and norbornene, namely 2,3,4,4a,6,10b-hexa-hydro-6-phenyl-1,4-methano-1H-dibenzo[b,d]thiopyran, was subjected to a single crystal X-ray diffraction analysis. A syn relationship between the two protons on C(α) next to the sulfur atom was confirmed in the crystal state and suggests that an intermediate precursor of the adduct may not be formed by an entirely concerted process or a rearrangement occurs after a precursor is formed. If a [4 + 2]-cycloaddition had occurred, a rearrangement seems required to explain the stereochemistry of the adduct. 13C and 1H NMR analyses were performed and, using the HETCOR 2-D technique, it was possible to assign many signals with confidence although it was not possible to do so with every signal. Models were used to substantiate the assignments in the NMR spectrum as well as in the ultraviolet spectrum of the title compound.