N-alkyl thiols

Porter MD, Bright TB, Allara DL, Chidsey CED (1987) Spontaneously organized molecular assemblies. 4. Structural characterization of n-alkyl thiol monolayers on gold by optical ellipsometry, infrared spectroscopy, and electrochemistry. J Am Chem Soc 109 3559-3568... 

The cross-coupling reaction proceeds through the initial oxidation of the more reactive thiol, followed by the gradual thiolysis of the formed disulphide by the less reactive thiol. The method is therefore useful for the cross-coupling of the reactive aryl and n-alkyl thiols with the less reactive f-alkylthiols. 

TABLE 10-4. FILMS OF n-ALKYL THIOLS ADSORBED ON CHROMIUM... 

Fenter P, Eberhardt A and Eisenberger P 1994 Self-assembly of n-alkyl thiols as disulphides on Au(111) Science 266 1216-8... 

To improve the compatibility of GNPs in LC host, both of the simple n-alkyl thiol and LC/mesogen molecules are used simultaneously to form mixed mono-layer. For example, nematic cyanobiphenyl end-functionalized alkylene thiol covered GNPs and its mixing with n-alkyl thiols (n = 6, 12) in two cyanobiphenyl nematic LC hosts (5CB and 8CB) were investigated [60]. By adding small quantities of alkyl thiolate-capped GNPs there was effectively reversed nematic LC orientation which further showed opto-electronic responses [61]. Recently,... 

Nuzzo, R. G., Korenic, E. M., and Dubois, L. H. (1990) Studies of the Temperature-Dependent Phase Behavior of Long Chain N-Alkyl Thiol Monolayers on Gold, J. Chem. Phys. 93, 767-773. 

The mevalonic acid model 2 has been synthesized from diacetone 3-deoxy-D-glucose (1) in many steps, as outlined in Scheme 1, and its analogue 3 with an additional hydroxyl group was made available by a similar reaction sequence starting from 2,4-O-benzylidene-D-glucitoL The preparation and liquid crystalline properties of dithioacetals 4, obtained from D-galactuionic acid n-alkylamides by treatment with n-alkyl thiols in the presence of trimethylsilyl chloride have been described. ... 

C. Naselli, J. F. Rabolt, J.D. Swalen, "Order-disorder transitions in Langmuir-Blodgett monolayers. 1. Studies of two dimensional melting by infrared spectroscopy", J. Chem. Phys., 1985,82(4), 2136-2140. R.G. Nuzzo, E.M. Korenic, L.H. Dubois, "Studies of the temperature-dependent phase behavior of long chain n-alkyl thiol monolayers on gold", J. Chem. Phys., 1990,93(1), 767-773. 

The reaction of 1-amino-1-deoxyketoses, and their N-alkyl and N-aryl derivatives, with alkyl or aryl isothiocyanates (Huber et al, 1960) was studied in more detail, and new 4-(alditol-l-yl)-l-alkyl(aryl)-3-alkyl(aryl)-l,3-dihydro-2H-imidazole-2-thiones were obtained. These compounds were used as starting materials for the synthesis of OL-histidines, DL-histidine-2-thiol, and other imidazole derivatives of biological interest. 

Several palladium catalysts for formation of aryl sulfides from aryl halides have been investigated more recently. A combination of Pd2(dba)3 and DPEphos catalyzed the formation of a broad range of diaryl sulfides in the presence of 1 mol.% palladium and NaO-t-Bu base in toluene solvent.12,rThe highest yields of alkyl aryl sulfides were obtained from aryl triflates and n-butyl thiol catalyzed by a combination of palladium acetate and BINAP. However, these reactions contained 10 mol.% catalyst, were long, and required deactivated aryl triflates. A combination of Pd2(dba)3 and DPPF catalyzed the coupling of thiols with resin-bound aryl halides.121... 

The base-catalysed addition of thiols to Jt-electron-deficient alkenes is an important aspect of synthetic organic chemistry. Particular use of Triton-B, in place of inorganic bases, has been made in the reaction of both aryl and alkyl thiols with 1-acyloxy-l-cyanoethene, which behaves as a formyl anion equivalent in the reaction [1], Tetra-n-butylammonium and benzyltriethylammonium fluoride also catalyse the Michael-type addition of thiols to a,P-unsaturated carbonyl compounds [2], The reaction is usually conducted under homogeneous conditions in telrahydrofuran, 1,2-dimethoxyethane, acetone, or acetonitrile, to produce the thioethers in almost quantitative yields (Table 4.22). Use has also been made of polymer-supported qua-... 

Chiral pyrrolo[d]thiepine 166 can be obtained efficiently in 63% yield starting from N-alkylated maleimide 164. Successive Michael addition of phenethyl thiol and regioselective reduction are followed by spontaneous loss of hydrogen by N-acyliminium intermediates 165 and 7r-aromatic intermolecular a-amidoalkylation... 

Organized multilayers of ferrocene alkyl thiol have been self-assembled on Au(lll) under conditions of controlled thiol concentration. Several methods, such as CV, ellipsometry, STM, AFM, and in situ FTIR spectroscopy have been applied in these studies in order to find out the differences between mono- and multilayers of the same compound [152]. Similar compounds, namely, short-chain alkyl thiols (n = 3-10) with ferrocene terminal group were allowed to form organized monolayers at Au(lll) surfaces [153]. 

Isothioureas can be prepared on insoluble supports by S-alkylation or S-arylation of thioureas (Entry 7, Table 14.6). Further methods for the preparation of isothioureas on insoluble supports include the N-alkylation of polystyrene-bound, A/,/V -di(alkoxy-carbonyl)isothioureas with aliphatic alcohols by Mitsunobu reaction (Entry 7, Table 14.6) and the addition of thiols to resin-bound carbodiimides [7]. Resin-bound dithio-carbamates, which can easily be prepared from Merrifield resin, carbon disulfide, and amines [76], react with phosgene to yield chlorothioformamidines, which can be converted into isothioureas by treatment with amines (Entry 8, Table 14.6). The conversion of support-bound a-amino acids into thioureas can be accompanied by the release of thiohydantoins into solution (see Section 15.9). The rate of this cyclization depends, however, on the type of linker used and on the nucleophilicity of the intermediate thiourea. 

In contrast, because of similar electronegativities, the transition state for hydrogen transfer from benzene thiol to a perfluoro-n-alkyl radical should have little polar character. In confirming the important role of polar effects in these hydrogen transfer processes, a good Hammett correlation was observed for the reduction of n- c7f15i by a series of arene thiols [141,143]. 

A better strategy for monoalkylation of primary aliphatic amines is their condensation with aldehydes or ketones followed by reduction of the resulting imine. Alternatively, primary amines can be converted into sulfonamides, which can be readily N-alkylated and then hydrolyzed (less readily) with strong acids [21-23] or cleaved with thiols (Scheme 6.32). 

---