S. Scheibye

Studies on organophosphorus compounds—XL: Reactions of ketones with 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide☆

Abstract Cyclohexanone and cyclopentanone react with 2,4 - bis - 4 - methoxyphenyl) - 1,3,2,4 - dithiadiphosphetane 2,4-disulfide (lawesson Reagent ( LR ) at 80° with formation of new spiro - 1,3,5,2 - trithiaphosphorines 1 and 2 , respectively. 2-Methyl and 2-phenylcyclohexanone also react with LR at 80° producing the enethiols 3 and 4 , which on storage are transformed into the sulfides 5 and 6 . Unsaturated cyclohexanones 7–9 are transformed into the corresponding thioketones 10–12 after reactions with LR at 60° for a few hours. 2-Hydroxyketones react with LR with formation of 1,3,2-oxathiaphospholes and similarly a 2-aminoketone gave a 1,3,2-thiazaphosphole. Aromatic ketones, reacted with LR to give corresponding thioketones. Thiofluorenone dimerized to form the cyclic disulfide 31 , as proved by X-ray analyses.

Studies on organophosphorus compounds—XLI: Formation of 3-pyrazoline-5-thione disulfides from 3,5-pyrazolidinediones. C-alkylation of 3,5-pyrazolidinediones

Abstract 4-Substituted-1,2-diphenyl-3,5-pyrazolidinediones (Phenylbutazone analogous) 1a–d react with 2,4-bi-(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-difulside (Lawesson Reagent (LR) with formation of the corresponding 3,3′-dithiobis (1,2-dihydro-3 H -pyrazole-5-thione)s 2a–d . When the 4-substituent contains a sulfoxide group this is deoxygenated to the sulfide by LR at room tmeperature. 1-Phthalazinone-4-thione, 1,4-phthalazine-dithione and ethyl aminothioxoacetate have also been prepared from the corresponding carbonyl compounds. Alkylation or acylation of 2a–d yielded 3H-pyrazole-3-thione derivatives 8 and 9 . Alkylation of 1 with MeI in the presence of Et 3 N at room temp. yielded the C-alkylated products 10 exclusively. X-RAy crystallographic investigations of 2b and 9a are presented.

Electron impact studies. CXXV. Negative ion mass spectra of thiobenzamides. Dual mechanisms for loss of NO∓ from o-nitrothiobenzamides

Abstract Molecular anions of thiobenzamides ArC(S)N(R1R2) (R = alkyl) fragment by the cleavages M−∓ → (M - R1∓)− and M−∓ → (M - R2∓)−, with loss of the larger alkyl predominating. o-Nitrothiobenzamides o-NO2C6H4C(S)N(R1R2) eliminate R1R2N∓ from their molecular anions following cyclisation between the two functional groups. The observation of composite metastable peaks for loss of NO∓ from the molecular anions of the o-compounds shows that two mechanisms are operating. It is proposed that the process having the larger T value corresponds to the normal loss of NO∓ from −NO2−∓, whereas that having the smaller value arises from loss of NO∓ from an −NOS−∓ group formed by rearrangement.

THIATION OF CARBONYL COMPOUNDS WITH THE DIMER OF P-METHOXY-P-THIONOPHOSPHINSULFIDE

Abstract Recent studies on thiation of carbonyl compounds with organic P,S-compounds have shown that p-methoxyphenyl-thionophosphinsulfide (1) is the most effective thiation reagent for ketones, carboxamides, esters, and thioloesters hitherto known.

SYNTHESIS OF SALICYLTHIOAMIDES AND 4 H-1, 3, 2 BENZOXAZAPHOSPHORIN-DERIVATIVES

Abstract Recent studies have shown that the dimer of p-methoxyphenylthionophosphinesulfide, 1, is a very superior thiation reagent, as ketones, amides, and esters are in most cases quantitatively converted to their thio-analogues.