The Chemistry of Sulfur Curing. IV. Effects of Organic Accelerators on the Reaction of Cyclohexene with Sulfur

1968 ◽  
Vol 41 (5) ◽  
pp. 1339-1347 ◽  
Author(s):  
James R. Wolfe
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Major Product ◽  
Lithium Aluminum ◽  
Radical Mechanism ◽  
Secondary Products ◽  
Tetramethylthiuram Disulfide ◽  
Hydride Reduction ◽  
Free Radical Mechanism ◽  
Cis And Trans

Abstract Cyclohexene reacts with sulfur at 140° in the presence of zinc dimethyldithio-carbamate, tetramethylthiuram monosulfide, or tetramethylthiuram disulfide, to produce 2-cyclohexene-1-thiol as the major product after lithium aluminum hydride reduction of the polysulfide compounds. Secondary products are cis- and trans-1, 2-eyclohexanedithiol and cyclohexanethiol. Zinc dimethyldithiocarbamate is postulated to promote the reaction via an ionic mechanism as it causes more trans than cis-1, 2-cyclohexanedithiol to be formed. Tetramethylthiuram monosulfide and disulfide are postulated to promote the reaction via a free radical mechanism as they cause more cis- than trans-1, 2-cyclohexanedithiol to be formed.

Synthesis oftrans- and cis-α-damascone

1978 ◽  
Vol 56 (10) ◽  
pp. 1368-1371 ◽  
Author(s):  
Hsing-Jang Liu ◽  
Hing-Kwok Hung ◽  
George L. Mhehe ◽  
M. L. Duarte Weinberg
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Complete Recovery ◽  
Lithium Aluminum ◽  
Magnesium Bromide ◽  
Keto Ester ◽  
Keto Esters ◽  
Hydride Reduction ◽  
Cis And Trans ◽  
Cis Isomer

Se lective thioketalization of a mixture of keto esters 5 and 6 resulted in the exclusive formation of thioketal 7 and complete recovery of keto ester 6. Lithium aluminum hydride reduction of thioketal 7 followed by Moffatt oxidation of the resulting alcohol 8 gave aldehyde 10 which on treatment with a mixture of cis- and trans-1-propenyl magnesium bromide afforded trans- alcohol 11 and its cis isomer 12. Manganese dioxide oxidation of alcohol 11 followed by desulfurization gave trans α-damascone (3). Similarly, alcohol 12 was converted to cis-α-damascone (4).

Reduction of Some Alkylisoxazoles with Lithium Aluminum Hydride

1975 ◽  
Vol 53 (20) ◽  
pp. 3011-3013 ◽  
Author(s):  
A. L. Khurana ◽  
A. M. Unrau
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Major Product ◽  
Major Constituent ◽  
Lithium Aluminum ◽  
Hydride Reduction

Lithium aluminum hydride reduction of alkyl substituted isoxazoles gave a variety of products. The major constituent was identified (i.r., n.m.r., m.s.) as hydroxyethylaziridine. Specifically, reduction of 3,4,5-trimethylisoxazole gave as the major product 2,3-dimethyl-3-β-hydroxyethylaziridine. Two of the more prominent minor products were identified as 2,3-dimethyl-3-ethylaziridine and 4-amino-3-methyl-2-pentanol. The corresponding products were identified when 3,5-dimethylisoxazole was reduced with LAH.

STEROIDS: I. 12β-METHYL-12α-HYDROXYPROGESTERONE

1961 ◽  
Vol 39 (3) ◽  
pp. 548-554 ◽  
Author(s):  
George Just ◽  
R. Nagarajan
Keyword(s):  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Major Product ◽  
Lithium Aluminum ◽  
Hydride Reduction

Lithium aluminum hydride reduction of 3α,12α -diacetoxypregnan-20-one (Ia) gives as the major product pregnane-3α,12α,20β-triol (III), whereas the reduction of the corresponding dihydroxypregnanone I affords mainly the epimeric 3α,12α,20α-triol II. Triol III was transformed to 12β-methyl-12α-hydroxyprogesterone (VIII).

The Chemistry of Sulfur Curing. III. Effects of Zinc Oxide on the Mechanism of the Reaction of Cyclohexene with Sulfur

1968 ◽  
Vol 41 (5) ◽  
pp. 1329-1338 ◽  
Author(s):  
James R. Wolfe ◽  
Thomas L. Pugh ◽  
A. Stanley Killian
Keyword(s):  
Zinc Oxide ◽  
Aluminum Hydride ◽  
Major Product ◽  
Lithium Aluminum ◽  
Chain Reaction ◽  
Radical Chain ◽  
Hydride Reduction ◽  
Cis And Trans ◽  
Radical Chain Reaction ◽  
Mechanism Of The Reaction

Abstract Reaction of cyclohexene and sulfur at 140° followed by lithium aluminum hydride reduction of the polysulfide products results in the formation of cyclohexanethiol, 2-cyclohexene-1-thiol, cis- and trans-1, 2-cyclohexanedithiol, and cyclohexyl sulfide. If zinc oxide is present during the reaction, trans-1, 2-cyclohexanedithiol is the major product. In the absence of zinc oxide, cis-1, 2-cyclohexanedithiol is the major product. It is postulated that in the absence of zinc oxide the reaction proceeds via a free radical chain involving polysulfenyl radicals accompanied by a secondary polar addition reaction of hydrosulfide products with cyclohexene. Zinc oxide when present is postulated to initiate an ionic chain reaction which, due to its greater velocity, dominates the radical chain reaction.

Free Radical Substitution Reactions of Sulfur Monochloride. A Limited Synthesis of Mercaptans

1973 ◽  
Vol 51 (20) ◽  
pp. 3366-3372 ◽  
Author(s):  
Dennis D. Tanner ◽  
Brian G. Brownlee
Keyword(s):  
Free Radical ◽  
Lithium Aluminum Hydride ◽  
Elemental Sulfur ◽  
Aluminum Hydride ◽  
Lithium Aluminum ◽  
Substitution Reactions ◽  
Sulfur Monochloride ◽  
Hydride Reduction ◽  
Abstraction Reaction ◽  
Radical Substitution

The photolysis of sulfur monochloride with a series of saturated aliphatic hydrocarbons yielded alkyl chlorides, di- and polysulfides, hydrogen chloride, and elemental sulfur. The free radical substitution reactions leading to the production of alkyl chloride and the di- and polysulfides were shown to proceed via a chlorine atom abstraction reaction. The major products, the di- and polysulfides could be transformed quantitatively, by lithium aluminum hydride reduction into their corresponding mercaptans. The reaction describes a simple free radical route to the synthesis of a variety of alkyl mercaptans.

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