Giving Other Derivatives

Aminothiazole itself (104a), R, = R2 = H (an intermediate in the preparation of sulfathiazole), was synthetized as early as 1888 from a,p-dihalogenoethylethers, which give chloroacetaldehyde in addic medium (8). Many other derivatives have now been used for this synthesis, and they are listed in Table IT12. All give excellent yields. 

Organosodium compounds are prepared from sodium and other organometaUic compounds or active methylene compounds by reaction with organic haUdes, cleavage of ethers, or addition to unsaturated compounds. Some aromatic vinyl compounds and aHyUc compounds also give sodium derivatives. 

Other Derivatives and Applications. Copolymerization of DCPD with other unsaturated substances has received wide attention, and several useful appHcations have been developed. With drying oils (qv) thermal copolymerization leads to the production of resinous products, the so-called bodied oils, that give improved drying and result in paint and varnish coatings of greater resistance to weathering. 

Other Derivatives and Reactions. The vapor-phase condensation of ethanol to give acetone has been well documented in the Hterature (376—385) however, acetone is usually obtained as a by-product from the cumene (qv) process, by the direct oxidation of propylene, or from 2-propanol. 

Methylpyridazine gives the pyridazine Reissert compound (105) with trimethylsilyl cyanide and freshly distilled benzoyl chloride. On the other hand, when pyridazine or 3-methylpyridazine reacts with undistilled benzoyl chloride the bicyclic compounds (106) are formed and these react with dimethyl acetylenedicarboxylate in anhydrous DMF to give pyrrolopyridazine derivatives (107 Scheme 30) (81JHC443). 

The most useful syntheses of pyridazines and their alkyl and other derivatives begins with the reaction between maleic anhydride and hydrazine to give maleic hydrazide. This is further transformed into 3,6-dichloropyridazine which is amenable to nucleophilic substitution of one or both halogen atoms alternatively, the halogen(s) can be replaced by hydrogen as shown in Scheme 110. In this manner a great number of pyridazine derivatives are prepared. 

Dimethyl-1,2,4-triazolium iodide with palladium acetate yields the carbene adduct 182 (97JOM(530)259). Under water it undergoes cis-trans isomerization to 183. Some other derivatives were reported in 1981 (81BCSJ800). 1,1 -Methylenebis(4-alkyl-l,2,4-triazolium)diiodides (alkyl = /-Pr, n-Bu, octyl) with palladium(II) acetate give the mononuclear complexes [L Pdl ] (99EJIC1965), where L2= l,l -methylenebis(4-R-l,2,4-triazol-2-ylidene) (R = /-Pr, n-Bu, octyl). Thermolysis of the products in THF gives the rran -dinuclear complexes 184... 

The action of triethylamine or 4-methylmorpholine on the imidazole derivatives 1 results in the formation of 4,5-dihydro-l/f-l,2-benzodiazepines 2, which eliminate imidazole on heating with ethanolic sodium ethoxide to give H-, 2-benzodiazepines 3.121 Details for compound 3 (R1 = Ph, R2 = Me) only were reported it was stated that other derivatives were obtained similarly but details were not given. 

The 1.4-dihydro-l,4-diazocines prepared from iyn-benzene diimines (Section 1.4.1.2.) can be transformed to other derivatives by exchange of the substituents at nitrogen. For this purpose, the dipotassium salt of 1,4-diazocine is generated and then reacted with appropriate electrophiles. For example, reduction of the bistosyl derivative 3 gives a relatively stable dianion, a lOrr-electron system analogous to cyclooctatetraene dianion, which on protonation clearly gives the parent l,4-dihydro-l,4-diazocine (4, E = H) as the only product. 

Reaction of a-phenylsulfinyl acetate or ethyl a-(t-butylsulfmyl)acetate with one equivalent of ethylmagnesium bromide or iodide was shown to give the corresponding Grignard reagent 129 or 132, which upon reaction with carbonyl compounds afforded the corresponding adducts. Thus Nokami and coworkers prepared ethyl / -hydroxycarboxylates 130167, jS-keto esters 131168, a,/J-unsaturated esters 133169 and other derivatives by this method. 

Metallic tin reacts with methyl halides and 2-halogenopropanoates at 135°, catalyzed by magnesium and butyl iodide in tetrahydrofuran, to give compounds MeSnXjCHgCHgCOjR, from which various other derivatives were prepared (42). 

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