Dimethyl thiourea

Fig. 16. [18]Crown-6 N,N dimethyl thiourea 1 2 complex the guest molecules are related by a center of symmetry 281...

Both 1 1 and 2 1 complexes of Af,.ZV-diethyl- and N,iV-dimethyl-thiourea with zinc, cadmium and mercury halides have been prepared. The 2 1 complexes are either monomeric and tetrahedral or polymeric and halogen-bridged with octahedral metal coordination the 1 1 complexes also possess a polymeric, halogen-bridged structure, but with tetrahedral metal coordination.894 5... 

In a subsequent study, the synthesis of urea and thiourea derivatives of types 3a and 3b were undertaken in an attempt to obtain new hosts that might yield more stable complexes with glutamic acid (of types 4a and 4b) and that might, in fact, hold together in polar solvents. The rationale for the design was based on the previously documented observation that both 1,3-dimethylurea and 1,3-dimethyl-thiourea form stable host-guest complexes with acetate in deutero-dimethyl sulfoxide the K values for the latter are 45 dm moF and 340 dm moF , respectively. 

Studies of oxidation reactions of differing substrate types have been described. The nature of oxidant species in HCIO4 and H2SO4 media has been examined by investigation of catalysis of the Ce -Hg reaction. It is suggested that at 2.OM-HCIO4 the iridium(iv) is hydrolysed with protonation constant of 0.4 for [Ir(H20)s0H] +. Most kinetic studies, however, refer to reaction of the hexachloro and hexabromo ions. The oxidation of thiourea (tu), iV,iV -dimethyl-thiourea (dmtu), and 2-imidazolidinethione (it) follows a rate law second order in [substrate] and first in [Ir "]. The rate of oxidation follows the reactivity trend established previously for aquo-metal ions. The mechanism proposed involves rapid pre-equilibria followed by disulphide radical formation,... 

In the central nervous system, OONO" induced modification of neuronal function. It stimulated the release of neurotransmitters including Y-amino-butyric acid (GABA) and acetylcholine from mouse cerebral cortical neurones (Ohkuma etal. 1995). Hydroxyl radical scavengers such as NdST-dimethyl-thiourea (DMTU), mannitol, and uric acid signifi-... 

Various compounds have been tested in animal studies in the quest to develop an effective chlorine-specific treatment based on its mechanism of action (Table 24.4). The evaluated compounds include the antioxidants dimethyl-thiourea, ascorbic acid, N-acetyl-L-cysteine, and deferoxamine mesylate (Leustik et al., 2008 McGovern et al., 2010 Zarogiannis et al., 2011) sodium nitrite (Yadav et al., 2011) the corticosteroids mometasone, budesonide, and dexa-methasone (Ghen et al., 2013 Jonasson et al., 2013), the type 4 phosphodiesterase inhibitor rolipram (Chang et al., 2012), and the p2-agonist arformoterol (Song et al., 2011). 

CdCujS Sn F43m a=5.65 Z=1 Zincblende-type. X, powder. Thin layers prepared by spray pyrolysis, aqueous solutions of stoichiometric amounts of the metal chlorides and dimethyl thiourea sprayed onto a heated 79 Pam 1... 

Other sulfur compounds such as thiourea, ammonium dithiocarbamate, or hydrogen sulfide also lead to 2-mercaptothiazoles. Thus thiourea has been used in the syntheses of 4,5-dimethyl (369) and 4-aryl-2-mercapto-thiazoles (Table 11-30) (519). The reactions were carried out by condensing the ia -thiocyanatoketones with thiourea in alcohol and water acidified with hydrochloric acid. By this procedure, 4-aryl-2-mercaptothiazoles were obtained in yields of 40 to 80% with bis-(4-aryl-2-thiazolyl) sulfides as by-products (519). These latter products (194) have also been observed as a result of the action of thiourea on 2-chloro-4-arylthiazole under the same experimental conditions. They can be separated from 2-mercaptothiazoles because of their different degrees of solubility in sodium hydroxide solution at 5%. In this medium bis-(4-phenyl-2-thiazolyl)sulfide is... 

DiaminO 4,4-dimethyl-l,3,5-thiadiazine hydrobromide was isolated as by-product (418). Benzene sulfonates of cyanohydrin prepared from sodium cyanide and an halobenzoaldehyde, when treated with thiourea or its derivatives, afford 2,4-diamino-5-(p-halogenophenyl)-thiazole benzene sulfonates (447). Similarly, cyanoamido thiocarbamates obtained from cyanamide and isothiocyanates yield substituted 2,4-diaminothiazoles (598). 

The primary synthesis of alkoxypyrimidines is exemplified in the condensation of dimethyl malonate with O-methylurea in methanolic sodium methoxide at room temperature to give the 2-methoxypyrimidine (854) (64M207) in the condensation of diethyl phenoxymalonate with formamidine in ethanolic sodium methoxide to give the 5-phenoxypyrimidine (855) (64ZOB1321) and in the condensation of butyl 2,4-dimethoxyacetoacetate with thiourea to give 5-methoxy-6-methoxymethyl-2-thiouracil (856) (58JA1664). 

Many other examples are known of non-selective reactions of halo groups in pyridopyridazines with amines, alkoxides, sulfur nucleophiles such as hydrosulfide and thiolate ions, or thiourea, hydrazine(s), cyanide ion and dimethyl sulfoxide, or on catalytic reduction. 

In contrast to the above additions A-allyl- and substituted A-allyl-amides, -urethanes, -ureas and -thioureas undergo intramolecular cyclization only in 6(3-96% sulfuric acid to give the corresponding oxazolinium and thiazolinium salts. Treatment of these cations with base yields 2-oxazolines and 2-thiazolines in moderate to good yields. The reaction is illustrated by the conversion of A-2-phenylallylacetamide (342) into 2,5-dimethyl-5-phenyl-2-oxazoline (343) in 70% yield 70JOC3768) (see also Chapter 4.19). 

Nucleophilic catalysis is also observed with iodide ions. Fluoride ion does not form nitrosyl fluoride under diazotization conditions, as is to be expected from Pearson s hard and soft acids and bases principle which was discussed briefly in Section 3.2. More recently, nucleophilic catalysis has also been shown to occur with thiocyanate ion (SCN ), thiosulfate ion (HS2Of), dimethyl sulfide, and thiourea (H2NCSNH2) or its alkyl derivatives (see below). 

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