2- Mercaptopyrimidines, reaction with

A. 2-Mercaptopyrimidine hydrochloride. Thiourea (61 g., 0.80 mole) and 600 ml. of ethyl alcohol (Note 1) are placed in a 2-1. three-necked flask equipped with a sealed mechanical stirrer, a reflux condenser, and a stopper. The stirrer is started, and 200 ml. of concentrated hydrochloric acid is added in one portion through the open neck. After several minutes, when the warm mixture has become homogeneous, 176 g. (0.80 mole) of commercial-grade 1,1,3,3-tetraethyoxypropane (Note 2) is added rapidly, the open neck is stoppered, and the yellow solution is boiled for about 1 hour with continuous stirring. During this period the reaction mixture darkens in color and the product separates (Note 3). 

The reaction mixture is chilled to about 10° by immersing it in an ice bath for about 30 minutes, and the yellow crystalline precipitate is collected on a Buchner funnel. It is then washed with 100 ml. of cold alcohol and air-dried at room temperature. The yield of 2-mercaptopyrimidine hydrochloride is 71-76 g. 

The synthesis of 2-substituted pyrimidines from 1,3-dicarbonyl compounds and urea derivatives was first described by Evans2 and was later improved by Hunt, McOmie, and Sayer3 for the preparation of 2-mercapto-4,6-dimethylpyrimidine. Burness4 employed 3-ketobutyraldehyde acetal in this procedure to give 2-mercapto-4-methylpyrimidine. 2-Mercaptopyrimidine has been prepared from 1,1,3,3-tetraethoxypropane and thiourea by variations of this basic method 3 6 6 as well as by the reaction of 2-chloropyrimidine with thiourea 1 or sodium hydrosulfide.8... 

The mono- and bidentate complexes (425) and (426), respectively, form from the reaction of [Ir(cod)Cl]2 with mercaptopyrimidine.6 2 (426) reacts with CO, yielding the dicarbonyl analogue through displacement of cod. One CO ligand may be replaced by PPh3, but further addition of PPh3 results in a five-coordinate species. 

Sodium azide may be analyzed by reacting the aqueous solution with iodine. The reaction is induced by 2-mercaptopyrimidine (Kurzawa 1987). The excess of iodine is back-titrated using potassium iodide, sodium thiosulfate, and starch indicator. The azide functional group may be identified by FTIR. 

S-donor ligands. Reaction of the 2-mercaptopyrimidines (84 R = H, Bu , Bz, Ph, p-tolyl, o-MeOCgH, or m-NOjCgHJ with AgNOj in ammoniacal aqueous ethanol has yielded the pale yellow precipitates (85). " This behaviour... 

Zakrzewski, R. Ciesielski, W. Detection of mercaptopyr-idines and mercaptopyrimidines in planar chromatography with iodine-azide reaction as a detection system. J. Chromatogr. B, 2005, 824, 222-228. 

Arsenic-containing antibacterial polymers have been prepared by the reaction of triphenylarsenic dichloride with 2,4-diamino-6-mercaptopyrimidine. 

A mixture of 2, 3 -0-isopropylideneuridine, 2-mercaptopyrimidine, and dimethyl-formamide dineopentyl acetal refluxed in benzene under anhydrous conditions -> thioether (Y 73%) refluxed 0.5 hr. with Raney-Ni W4 in ethanol 2, 3 -0-isopropylidene-5 -deoxyuridine (Y 70%). - This reaction affects prim, hydroxyl groups selectively therefore, protection of the functional groups is not required. F. e. s. A. Holy, Tetrah. Let. 1972, 585. 

Scheme 114 Reaction of 2-mercaptopyrimidines with CF3COOH-XeF2...

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