1,2 - Dithiolane - 3 - carboxylic acid

C3S2 s s — — — l,2-Dithiolane-4-carboxylic acid 3-phenyl-l,2-dithiolylium iodide 4-methyl-1,2-dithiole-3-thione ... 

AC85 C eOsSg l,2-dithiolane-3- carboxylic acid EtOH 25 PO buffer - 5-0 - SME/ - --2 C-l... 

Appleton DR, Copp BR (2003) Kottamide E, the First Example of a Natural Product Bearing the Amino Acid 4-Amino-l,2-dithiolane-4-carboxylic Acid (Adt). Tetrahedron Lett 44 8963... 

Dithiolanes (1), in contrast to other dithioles, are not planar. In the carboxylic acid (28a) the CSSC dihedral angle is 26.6° (B-61MI43100), leading to a strain of 67 kJ mol-1. These compounds are unstable and the parent may be obtained only in dilute solution. Lipoic acid (29) is more stable, but does polymerize. The instability may account for its particular reactivity (B-61MI43101). l,2-Dithiol-3-ones (3a) and -3-thiones (3b) are very stable, as is evident from their modes of formation. Simple l,2-dithiol-3-imines (3c) are also stable, but some readily interconvert to isothiazoline-3-thiones (30) (Section 4.31.3.2). 

The first peptides with an incorporated 4-amino-l,2-dithiolane-4-carboxylic acid residue (Adt), represented by structures 319 <2000BMCL1585>, 320 <2002BMCL147>, and 321 <2005PES104>, were synthesized in order to restrict their conformational mobility and stabilize defined secondary structures, thus making them chemically more stable and biochemically active. 

Kottamide-E. In a 2003 report, Appleton and Copp reported the isolation and characterization of another analogue in this sequence, kottamide-E, 33, which they described as the first example of a natural product bearing the amino acid 4-amino-l,2-dithiolane-4-carboxylic acid. All the nitrogens in the structure of 33 are protonated and were detected in a HSQC spectrum. The authors, however, also report the use of a 6 Hz optimized HMBC spectrum in the elucidation of the structure of the molecule. 

Reaction of 1,2-ethanedithiol with boron trifluoride dimetbylsulfide complex gives (367) which is a useful reagent for the one-step conversion of carboxylic acids RCO2H into 1,3-dithiolanes (368) (Equation (77)) <89MI 312-01>. 

Appleton, D. R, Copp, B. R, (2003). Kottamide E, the first example of a natural product bearing the amino acid 4-amino-l,2-dithiolane-4-carboxylic acid (Adt). 

Dithioacetals, 1,3-dithianes or 13-dithiolanes are prepared by reaction of the corresponding carbonyl compound in the presence of an acid catalyst (cone. HQ, Lewis acids such as Znh, BFs EtaO, TMS-Cl, etc.) with a thiol or dithiol. Silica gel treated with thionyl chloride was found to be an effective as well as selective catalyst for thioacetalization of aldehydes. Thioacetalization can also be achieved using a (polystyryl)diphenylphosphine-4odine complex as a catalyst Conversion of aldehydes or acetals into 1,3-dithianes is achieved with the aid of organotin thioalkoxides and organotin triflates or with 2,2-di-methyl-2-sila-l,3-dithiane. Direct conversion of carboxylic acids to 1,3-dithianes can be carried out by reaction with 1,3,2-dithiabomenane-dimethyl sulfide and tin(II) chloride or 1,3,2-dithiaborolene with trichloromethyllithium followed by basic hydrolysis. 

Isobutyric acid is the precursor of asparagus acid (l,2-dithiolane-4-carboxylic acid) found in... 

Tributyltin hydride has been applied to the selective reduction of acid chlorides and 1,3-dithiolanes/ and to the conversion of carboxylic acids and isocyanides " to alkanes. Acyl cyanides are obtained from the treatment of acid chlorides with tributyltin cyanide/ and cyclic ketones are converted into nitro-olefins via the corresponding trimethylvinyltin compound. ... 

Cyclic Disulphides.— Most of the syntheses of these types of compounds involved oxidation of the open-chain dithiols. Asparagusic acid, or 1,2-di-thiolan-4-carboxylic acid, a new plant-growth inhibitor, has been isolated from extracts of etiolated asparagus and its structure confirmed by synthesis. Brugeriol and isobrugeriol, trans- and cis-4-hydroxy-l,2-dithiolan... 

---