Methanol formamidines

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). 

Different substrates have been tested under the following conditions 300 ml stainless steel autoclave 0.25 moles of substrate 2.0 g Raney nickel (60% in water) 1.5 g (0.014 moles) of formamidine acetate 120 ml methanol temperature 80°C H2 pressure 12 bar, 1500 rpm. 

The halonitro compounds and the methanol used were of purum or pract. quality from Fluka. The amidine derivatives (in the form of their salts) were purchased from Fluka or Aldrich (purum or pract.). The N,N-dialkyl-formamidine acetates were prepared by analogy to a published procedure (ref. 8) from cyanamide and used as isolated (containing ca. 10% ammonium acetate). 

Reaction time time and chemoselectivity for the hydrogenation of different substrates (formamidine acetate Raney nickel methanol 80°C 12 bar)... 

These anomers were separated by chromatography, whereupon each one deformylated with methanolic hydrogen chloride to give an inseparable anomeric mixture of hydrochlorides 297 and 298. The latter was reacted with formamidine acetate and triethylamine in refluxing ethanol to give directly 7-(2,3,5-tri-0-benzoyl-j3-D-ribofuranosyl)thieno[3,4-d]pyrimidin-4(3//)-one 299 and its a-anomer. 

Formycin A was initially isolated from rice mold <65JAN259> and identified <66JHC110, 66TL597) as 3-ribofuranosylpyrazolo[4,3-G ]pyrimidine-7-amine (54a). The reported synthesis utilizes the pyra-zole derivative (522) as starting material which is converted in situ on treatment with zinc dust in methanol in the presence of ammonium chloride into the amine (523) which is then reacted with formamidine to yield formycin A after deprotection (Scheme 53) <78CCC1431>. 

There are standard methods available for synthesis of amidines 10] and guanidines. In particular, reaction of an acylated thiourea with an amine, followed by removal of the acyl group(s) from the acylguanidine intermediate provides a mild and efficient synthesis [11]. When dihydroxyacetonc is treated with formamidine acetate in liquid ammonia, imidazole-4-methanol is isolated in 65-70% yield as its hydrochloride (3) (Scheme 4.3.2). This convenient synthesis is much less tedious than the old approach based on the reaction of fructose with ammonia [16]. 

Formamidines were prepared from carbon monoxide, methanol, and amines in the presence of DBU and a mixture of a Group VA Lewis base and alkene oxide (84EUP107441). 

Hydrosilylation of carbodiimides proceeds only at 140-200°C in the presence of PdClj or Rh(PPh3)3Cl to give )V-silylformamidines 3. The fV-silylformamidine thus obtained reacts with methanol and acyl chlorides to afford the corresponding formamidines and A -acyl formamidines, respectively ... 

A new organonitrogen insecticide, hf-(2,4-dimethyl-phenyl) ff -methyl-formamidine, was determined on silica gel G plates developed with benzene-cyclohexane-methanol (1 1 1) mobile phase. The compound was detected with bismuth hyponitrite and potassium iodide reagents (73a) (Table 4). 

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