Benzyl mercaptan, derivative

While carboxylate anions do not add to the imonium function of ketone derived enamines, such as morpholinocyclohexene, when these are combined with carboxylic acids (38), the addition of thiophenol or benzyl mercaptan leads to a-aminothioethers (509,510). 

Reaction of 2-chloromethyl-4//-pyrido[l,2-u]pyrimidine-4-one 162 with various nitronate anions (4 equiv) under phase-transfer conditions with BU4NOH in H2O and CH2CI2 under photo-stimulation gave 2-ethylenic derivatives 164 (01H(55)535). These alkenes 164 were formed by single electron transfer C-alkylation and base-promoted HNO2 elimination from 163. When the ethylenic derivative 164 (R = R ) was unsymmetrical, only the E isomer was isolated. Compound 162 was treated with S-nucleophiles (sodium salt of benzyl mercaptan and benzenesulfinic acid) and the lithium salt of 4-hydroxycoumarin to give compounds 165-167, respectively. 

Using this procedure, the S-labeled rhena-/8-ketoimine derivatives of benzyl mercaptan, ethanethiol, Me3COC(O)NH0H2CH2SH, iV-acetyl-L-cysteine, and iV-acetyl-D,L-penicillamine have been prepared. 

Despite the many simple methods for preparation of carboxylic esters and thioesters, in some instances, use of 1-acylbenzotriazoles 915 as O and S acylating agents may be advantageous. For example, easy to prepare salicylic acid derivative 941 reacts with cyclopentanol under microwave irradiation to give 92% yield of cyclopentyl salicylate in 10 min <2006JOC3364>. In another example, L-phenylalanine derivative 942 reacts with benzyl mercaptan... 

CV investigations of 6-mercaptopurine and 8-mercaptoquinoline SAMs on pc-Au electrodes have been presented by Madueno et al. [186] and He etal. [187], respectively. Several model electrode reactions involving various redox probes were studied using such modified electrodes. Baunach and Kolb etal. [188] have deposited copper on disordered benzyl mercaptan film on Au(lll) surfaces. They have also studied the behavior of benzyl mercaptan SAM on Au(lll) in H2SO4 solution using CV and STM. Structural and electrical properties of SAMs based on tetrathiafulvalene derivatives on Au(lll) were investigated. These mono-layers were disordered, or at least loosely... 

Substitution by the soft anion derived from diethyl malonate occurs with ring opening at the 6-position of 172. Subsequent cyclization gives the corresponding thiocarbonyl compound 173 after elimination of the labile benzyl mercaptan (Scheme 68) (83TL3713). It has been shown that 173 is different from its isomer (174) which is obtained elsewhere (81UP1). 

Whereas the results summarized in Scheme 4.32 were achieved under homogeneous reaction conditions, Colonna et al. reported the use of chiral phase-transfer catalysts for asymmetric addition of benzyl mercaptan and thiophenols to cyclohexenone and derivatives [55b], The best result was 85% yield and 36% enantiomeric excess in the addition of thiophenol to cyclohexenone, catalyzed by ca 0.4 mol% N-(o-nitrobenzyl)quininium chloride at 25 °C. In this experiment, CCI4 served as solvent and solid KF as the base. Finally, Aida et al. reported in 1996 that chiral... 

Individual amino acids show considerable differences in their propensity for racemization. This is exceptionally pronounced in derivatives of S-benzyl-cysteine, 0-benzyl-serine and S-cyanoalanine. The role of the substituent on the jS-carbon atom is not obvious. Early assumptions of j8-elimination, that is the reversible elimination-addition of benzyl mercaptane, benzyl alcohol or HCN, were not supported by the extensive studies of J. Kovacs. This example shows, however, that the azlactone mechanism, while it appears to be the most important pathway of racemization, is not the only process which leads to diminished chiral purity. For instance it is reasonable to consider that... 

Using a chiral primary amine salt derived from 9-amino-(9-deoxy)-e/>i-hydroquinine, Melchiorre et al. achieved an organocatalytic asymmetric protocol for the highly enantioselective sulfa-Michael addition, which was applicable to a large variety of a,p-unsaturated ketones. The highest enantioselectivities of up to 96% ee combined with high yields were obtained with benzyl mercaptan as a nucleophile, as shown in Scheme 1.69. 

An ethereal soln. of benzyl thiobenzoate added to a stirred suspension of LiAlH4 in ether, and the product isolated after 5 hrs. benzyl mercaptan. Y 85%. F. e., also in dioxane, steroid derivatives also with O-debenzoylation, s. P. A. Bobbio, J. Org. Chem. 26, 3023 (1961). 

Reaction of 2-fluoro-3-trifluoromethylfurans 235 with allyl alcohols followed by Claisen rearrangement directly produced butenolides 237 [145, 146]. Oppositely, allyl mercaptane formed stable substitution product 236 [146], A similar transformation was reported for benzyl alcohols. While benzhydryl and (2-thienyl)methyl groups migrated at room temperature directly furnishing butenolides 239, in the case of benzyloxy derivatives, heating at 120 °C was required to reach the transformation. On the other hand, stable up to 140 °C products 238 were formed in the reaction of benzylamine, benzyl mercaptane, and 2-(hydroxymethyl)pyridine [147]. 

Brown and Scholefield (63) found that benzyl- and ethylthiopropionate, but not thiolacetate, are converted to benzyl mercaptan or ethanethiol, respectively. Guinea pig mitochrondia in vitro convert ethylthioacetic acid to the corresponding CoA derivative (64). 

A comparison of the rate of conversion of a-tosylamino- 3-thiolactone and a-(A -methyl-A -tosyl-amino)-j3-thiolactone calculated from the change of specific rotation with time is shown in Figure 8. Both monomers were polymerized under the same conditions in bulk at 110 °C with 3.2% of benzyl mercaptan as initiator. It is evident that the A -tosylamino derivative polymerizes much faster than A -methyl-A/ -tosylamino- 3-thiolactone. 

Procedure In a 10-ml flask fitted with a reflux condenser are placed 0.1 ml of benzyl mercaptan, 2 ml of a 10% methanolic 2,4-dinitrochlorobenzene solution, 1 ml of N NaOH, and methanol until dissolution is complete. The solution is boiled for 20 min and then filtered, while hot, through a small folded filter. The filtrate is cooled in a refrigerator and the separated derivative is filtered off with suction. Yield, 78 mg mp 129 to 130 °C. 

Notes and discussion. This reaction affords the 2-phenyl-, ethyl- and benzyl thioglycosides of sialic acid on exposure to the corresponding mercaptans with enhanced (3-selectivity. In the literature, treatment of the P-penta-0-acetate derivative with thiophenol produces 81% of the P-phenylthioglycoside derivative together with 7% of the a-isomer. In practice, the phenylthioglycoside is prepared from the mixture of a- and P-penta-O-acetates (ratio ca. 1 8), which is subjected to the coupling reaction without fractionation of each isomer. 

Okawara et al., have prepared a vicinal mercaptan-containing polymer from poly(acryloyl chloride) (57) by similar procedures for preparation of XLIII. They also prepared a water-soluble dithiocarba-mate-polymer containing nitrogen in the backbone chain from poly(ethy-lene imine) 43,74) and a dithiocarbamate derivative from cellulose-acetate chloroacetate (43). Their photochemical behavior and ion-exchange capacity were similar to that exhibited by the poly(vinyl-benzyl)-derivatives. These polymers were also used as efficient heavy metal scavengers. 

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