A Novel Synthesis of tert‐ Alkyl Sulfides

Abstract

tert-Alkyl sulfides are conveniently prepared from a -( 1H-benzotriazol-I-y1)alkyl sulfides by displacement of the 1H-benzotriazol-I-yl group with Grignard reagents. The I-[a -(alkylthio)alkyl]-and I-[a -(arylthio)alkyl]-l Hbenzotriazole intermediates are easily available by several routes: i ) displacement of the halogen from appropriate halides by sodium salts of thiols, ii) condensation of IH-benzotriazole and thiols with carbonyl compounds, or iii) lithiation of N-substituted 1H-benzotriazoles and subsequent treatment with electrophiles.1. Introduction. -The most important classical methods for the preparation of alkylamines, alkyl ethers, and alkyl sulfides 2 (Z = NR, 0, and S, respectively) have involved formation of a C-N, C-0, or C-S bond by nucleophilic substitution at the central saturated C-atom in compounds of type 1 (X = halogen, sulfonate, or similar leaving group; Scheme 1 ). For amines, such methods are rarely high yielding because of the formation of mixtures [ 11. For ethers, this reaction (the Williamson synthesis) works well for the preparation of primary alkyl ethers 2a ( Z = 0), less well for see-alkyl ethers 2b (Z = 0), and not at all for tert-alkyl ethers 2c (Z = 0) [2]. For sulfides, satisfactory results are obtained for both 2a (Z = S ) and 2b (Z = S), but the method fails for tert-alkyl sulfides 2c ( Z = S) [3]. In fact, few methods are available for tert-alkyl sulfides, although they have been prepared in 20-76% yields from tertiary alcohols and thiols in glacial AcOH in the presence of HC10, [4]. tert-Butyl thiol was converted to tert-butyl sulfide by the Friedel-Crafts catalysts, AICI,, HF, BF, [5], or H,SO, [6]. It was also found that

Properties and Synthetic Utility ofN-Substituted Benzotriazoles

“…This acid-catalyzed condensation also succeeded with acetone and several cyclic ketones and gave mixtures of Bt 1 and Bt 2 isomers 146 while with 2-methylcyclohexanone it failed due to steric interactions, producing only 1-methyl-2-(phenylthio)cyclohexene. The ketal, 2,2-dimethoxypropane, gave the same reaction product as acetone, but in much better yield (72% vs 11%) …”

“…1-[α-(Alkylthio)alkyl]benzotriazoles react with Grignard reagents to give thioethers 883 in good yields (Table ) provided both R 1 and R 2 (Scheme ) are alkyl groups . Thus this method is applicable for the synthesis of tertiary alkyl thioethers which are not available by the classical Williamson synthesis, and the two procedures are again complementary.…”

ChemInform Abstract: Isomerization of N‐(α‐(Alkylthio)alkyl)‐ and N‐(α‐( Arylthio)alkyl)benzotriazoles.

“…The 13C-NMR spectra at 75 MHz were obtained on the same instrument with internal lock. N-[a -(Arylthio)alkyl]benzotriazoles 1-7 and N-[a -(alkylthio)alkyl]benzotriazoles 9, 10 were prepared according to the procedure in [6].…”

Nucleophilic Substitution of Benzotriazolylalkyl Chlorides with Grignard Reagents: A Direct Route to Benzotriazoloalkyl(hetero)aromatic Compounds

“…Many synthetically useful N-substituted benzotriazoles are of type Bt-C-X, where X is halogen, 1,2 amino-nitrogen, 3,4 amido-nitrogen, 5 oxygen 6 or sulfur. 7 Such adducts can react further either by Bt-C bond scission to form alkyleneonium cations or by C-X bond scission to give alkylenebenzotriazolium intermediates 3 (Scheme 1). Species 3 are normally generated from a-haloalkylbenzotriazoles (cf.…”