Carbon disulfide, reaction with pyrrole

Trofimov, B.A., L.N. Sobenina, A.I. Mikhaleva et al. 2000. Reaction of pyrrole anions with carbon disulfide. Synthesis of pyrrole-3-carbodithioates. Tetrahedron 56 7325-7329. 

Formamidine acetate (117) reacts with the pyrrole (118) in refluxing ethoxyethanol to give the pyrrolopyrimidine (119) which has been converted into the antibiotics toyocamycin, sangivamycin and tubercidin (Section 3.09.5) (69JA2102). A reaction with carbon disulfide... 

Alkylation of compound (1) to give l-(2-hydroxyethyl)pyrrolo[2,3-Z>]pyridine was achieved in 71% yield using fairly drastic conditions heating the reactants with aluminum chloride in carbon disulfide at 50°C for 30 min. To carry out alkylation at the 3-position of the pyrrole ring, a regiospecific alkylation was done via metallation of 3-bromopyrrolo[2,3-Z>]pyridine (35), giving the 1,3-dianion <84JHC42i>. In this manner, 3-(2-hydroxyethyl)pyrrolo[2,3-i]pyridine (36) was obtained in 57% yield. Further reaction to the bromo derivative (37) was carried out as outlined in Scheme 7. 

SAFETY PROFILE Poison by inhalation and ingestion. A corrosive eye, skin, and mucous membrane irritant. Potentially explosive reaction with water evolves hydrogen chloride and phosphine, which then ignites. Explosive reaction with 2,6-dimethylpyridine N-oxide, dimethyl sulfoxide, ferrocene-1,1 -dicarboxylic acid, pyridine N-oxide (above 60°C), sodium -L heat. Violent reaction or ignition with BI3, carbon disulfide, 2,5-dimethyl pyrrole + dimethyl formamide, organic matter, zinc powder. Reacts with water or steam to produce heat and toxic and corrosive fumes. Incompatible with carbon disulfide, N,N-dimethyl-formamide, 2,5-dimethylpyrrole, 2,6-dimethylpyridine N-oxide, dimethylsulfoxide, ferrocene-1,1-dicarboxylic acid, water, zinc. When heated to decomposition it emits highly toxic fumes of Cl" and POx. 

With phenolic ethers (16) and certain pyrroles (17), carbon disulfide (1) will insert into the nucleophilic carbon-hydrogen bond by a Friedel-Crafts-type reaction (Scheme 9). 

Enamines give 1,2-dithiole-3-thiones with carbon disulfide and sulfur.80 The reaction of aniline (44) described in Eq. (2) gives l,2-dithiole-3-thiones (7) as by-products along with pyrrole (45).81... 

Systematic investigations of the reaction of pyrroles with carbon disulfide in the superbase system KOH/DMSO [537-541] have shown that pyrrole anions, generated in this system, attack CS2 (20°C-25°C, 2 h) exclusively or mainly by the position 2 to afford pyrrole-2-carbodithioates. The latter, after alkylation with alkylhalides (20°C-25°C, 2 h), give the corresponding pyrrole-2-carbodithionic acid esters in 46%-75% yields (Scheme 2.71, Table 2.9) [537-540]. The only exception is unsubstituted pyrrole, which gives only pyrrole-l-carbodithioate [540]. 

Kobychev, V.B., N.M. Vitkovskaya, I.L. Zaitseva et al. 2001. Ab initio quantum chemical study of the reaction of pyrrole anions with carbon disulfide. Zh Strukt Khim 42 (4) 645-653. 

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