- Photochemical Induced Cyclisation of β-Keto Sulfides to Cycloalkanones
-
On UV irradiation, β-keto sulfides ArSCH2COPh (Ar = C6F5, C6CL5) cleaved to radicals ArS* and PhCOCH2* which, in one case (Ar = C6F5), were trapped by 1,1-diphenylethylene as the adduct PhCOCH2CH2C(Ph)2SC6F5.With diethyl ether as the solvent the major product was the monothioacetal ArSCH(Me)OEt.The keto sulfide 4-MeSO2C6H4SCH2COPh behaved similarly on irradiation in tetrahydrofuran.Irradiation of the unsaturated β-keto sulfides CH2=CH2COCH2SAr resulted in homolysis of the CH2-S bond to give a 2-oxohex-5-enyl radical, which subsequently cyclised; 4-(pentafluorophenylsulfanyl)cyclohexanone (when Ar = C6F5) and cyclohexanone (when Ar = p-tolyl) were the major products.With β-keto sulfides containing an aryl substituent, ethyl 2-benzyl-2-methyl-3-oxo-4-(pentafluorophenylsulfanyl)butanoate and 1,3-bis(p-tolylsulfanyl)propanone, irradiation resulted in cyclisation with loss of the sulfanyl substituent (probably involving electron transfer) to give 3-ethoxycarbonyl-3-methyl-1,2,3,4-tetrahydronaphthalen-2-one and 6-methylthiochroman-3-one, respectively, in high yield.
- Bahari, Kamarudin B.,Deodhar, Dinker J.,Hesabi, Masoud-M.,Hill, John,Kosmirak, Mario,et al.
-
p. 2393 - 2398
(2007/10/02)
-
- Benzyltriethylammonium tetrathiomolybdate: An improved sulfur transfer reagent for the synthesis of disulfides
-
Benzyltriethylammonium tetrathiomolybdate has been found to be a superior reagent for the conversion of alkyl halides to the corresponding disulfides in chloroform at room temperature.
- Ramesha,Chandrasekaran
-
p. 3277 - 3284
(2007/10/02)
-
- Process for producing pentachloronitrobenzene from hexachlorobenzene
-
Disclosed is a process for producing pentachloronitrobenzene (PCNB) by reacting hexachlorobenzene (HEX) with sodium hydrosulfide (NaSH) in the presence of sodium hydroxide (NaOH), sodium carbonate (Na2 CO3), or mixtures thereof to produce the sodium salt of pentachlorothiophenol (PCTP), followed by reacting it (or PCTP itself after acidifying) with nitric acid in the presence of sulfuric acid or oleum.
- -
-
-
- Replacement of Nitro Group of Pentachloronitrobenzene by Nucleophiles
-
Pentachloronitrobenzene (I) reacts with sodium hydroxide, sodium hydrogen sulphide, sodium methoxide and ammonia with replacement of the nitro group by -OH, -SH, -OCH3 and -NH2 groups respectively.Attempted replacement of the nitro group by -CN group has been unsuccessful.
- Hashem, A. I.
-
p. 1086 - 1087
(2007/10/02)
-
- Rearrangements of Vinylogous Acyl Chlorides, XXVI. - Z,E-Isomerizations of S-Alkyl and S-Aryl 2,3,4,5-Tetrachloro-2,4-pentadienethioates via 2H-Pyran Intermediates
-
The (Z,Z)-thioates 2 are prepared from the acyl chlorides 1 with thiols and triethylamine in ether or with thiolates in ethanol.They are stable below 100 deg C.At higher temperature the alkyl esters 2a - c and 2h, i lose alkyl chloride and decompose to th
- Roedig, Alfred,Fleischmann, Klaus
-
p. 1960 - 1971
(2007/10/02)
-
