Identification of carbonyl sulfide and sulfur dioxide in porcine coronary artery by gas chromatography/mass spectrometry, possible relevance to EDHF

Incubation of porcine coronary artery rings and cardiac muscle tissue in Krebs buffer followed by GC/MS analysis of the headspace gas revealed two gases, carbonyl sulfide (COS) and sulfur dioxide (SO(2)). The gases were identified by characteristic ions obtained by electron ionization, and by comparison of the retention time on a chromatographic column (GS GasPro) with standards of these gases. Stimulation of the arterial rings with acetylcholine and calcium ionophore A23187 increased the levels of SO(2) and COS in the vascular tissue. We also provide evidence that SO(2) could originate from disproportionation of a very unstable gas, sulfur monoxide (S=O). We suggest potential origins of these gases and discuss their relevance to endothelium-derived hyperpolarizing factor.

Synthesis of new cyclic thionosulfites

The reaction of a series of 1,2-diols with S(2)Cl(2), 1,1'-thiobisbenzimidazole (4a), and 1,1'-dithiobisbenzimidazole (4b) provides the corresponding thionosulfites, ROS(S)OR (2), in moderate to good yield.

Optimization of the synthesis of symmetric aromatic tri- and tetrasulfides

The reaction of aromatic thiols with sulfur dichloride and sulfur monochloride to form the corresponding aromatic trisulfides, 2a-d, and tetrasulfides, 3a-d, has been optimized with respect to yield and purity. The use of pyridine as an amine base and the use of freshly distilled sulfur monochloride (S(2)Cl(2)) serve as important alterations to the synthetic method. Their physical properties have been characterized, revealing some discrepancies with the literature.

Insertion of SO(2) into the S-S bond of Cp(2)MoS(2) and Cp(2)MoS(2)O to give molybdocene dithiosulfate and bis(O-alkylthiosulfates)

Cp(2)MoS(2), 3, reacts with SO(2) in CH(2)Cl(2)/EtOH mixtures to give Cp(2)MoS(3)O(2), 4, wherein the SO(2) has inserted into the S-S bond to give a dithiosulfate ligand. Crystal data for 4: P2(1)/n, a = 7.6782(6) A, b = 14.580(3) A, c = 10.2730(10) A, beta = 92.04(1) degrees, V = 1149(3) A(3), Z = 4. Cp(2)MoS(2)O, 5, reacts with SO(2) in CH(2)Cl(2) to give low yields of 4 plus other identified products. 5 reacts with SO(2) in MeOH and EtOH to give the corresponding bis(O-alkylthiosulfate), 6a and 6b, respectively. Crystal data for 6a: P 1 macro, a = 8.3226(13) A, b = 8.4736(11) A, c = 12.382(2) A, alpha = 87.803(11) degrees, beta = 77.758(11) degrees, gamma = 86.383(12) degrees, V = 851.4(2) A(3), Z = 2.

Dicubyl disulfide

Dicubyl disulfide (1) has been prepared in six steps from commercially available dimethyl-1,4-cubanedicarboxylate in 47% overall yield. In the final step, the previously unknown cubanethiol 2 was oxidized to disulfide 1. X-ray crystallography for 1 reveals the shortest tetragonal C-S bond on record (1.771 A). In contrast to previous generalizations, density functional theory calculations predict a low S-S rotation barrier similar to that for t-BuSSBu-t. Low-temperature (13)C NMR (600 MHz) confirms the prediction.