Ramon Pomes Hernandez

O-Isopropyl N-(2-furoyl)thiocarbamate

The title compound, C(9)H(11)NO(3)S, has crystallographic mirror symmetry, occurs in the thiocarbamate form and is stabilized in an s-cisoid,s-transoid conformation with respect to the C-N-C group. There are two intramolecular hydrogen bonds, one between the H atom of the N-H group and the O atom of the furan ring, and the other between the H atom of the secondary carbon of the isopropyl group and the S atom. The packing of the molecules is assumed to be dictated by van der Waals interactions.

3β-Acetoxy-5α,6β-dihydroxybisnorcholanic acid 22\rightarrow16 lactone

In the title compound, C 24 H 36 O 6 , the ester linkage in ring A is equatorial. The six-membered rings A, B and C have chair conformations. The five-membered ring D adopts a 13β,14α-half-chair conformation and the E ring adopts an envelope conformation. The A/B, B/C and C/D ring junctions are trans, whereas the D/E junction is cis.

3β-Acetoxy-5α,6β-di­hydroxybisnorcholanic acid 2216 lactone

In the title compound, C 24 H 36 O 6 , the ester linkage in ring A is equatorial. The six-membered rings A, B and C have chair conformations. The five-membered ring D adopts a 13β,14α-half-chair conformation and the E ring adopts an envelope conformation. The A/B, B/C and C/D ring junctions are trans, whereas the D/E junction is cis.

Ethyl methyl 1,4-dihydro-4-(3-nitrophenyl)-2, 6-bis(1-piperidylmethyl)pyridine-3,5-dicarboxylate.

In the title compound, C(28)H(38)N(4)O(6), the 4-aryl substituent occupies a pseudo-axial position approximately orthogonal to the plane of the dihydropyridine ring [88.1 (3) degrees ]. The dihydropyridine ring adopts a flattened boat conformation. The H atom on the pyridine N atom is involved in a bifurcated intramolecular hydrogen bond, the acceptors being the N atoms of the two piperidylmethyl groups [N.N 2.629 (4) and 2.695 (4) A].

5-Oxo-4-phenyl-1,2,3,4,5,7-hexahydrofuro-[3,4-b]-2(1H)-pyridone

The six-membered ring in the title compound, C 13 H 11 NO 3 , adopts a twist conformation and the lactone ring a planar conformation. The aryl group occupies a pseudo-axial position and is orthogonal to the plane through the pyridone ring. The molecules are linked by an intermolecular hydrogen bond between the N atom and the carbonyl-O atom of a neighbouring molecule [Nl… O5(x, y-1, z) = 2.820 (5) A].

5-Methoxycarbonyl-6-methyl-4-phenyl-3,4-dihydro-2(1H)-pyridone

Crystals of the title compound, C 14 H 15 NO 3 are stabilized by intermolecular hydrogen bonds between the NH group and one O atom of the carbonyl group. The six-membered ring adopts a twist conformation and the lactone ring a planar conformation.