- Metal free [4+1] and [5+1] annulation reactions to prepare heterocycles using DMF and its derivatives as one-carbon source
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1,2,4-Triazolo[3,4-a]pyridines and related heterocycles and substituted triazines were commonly discovered scaffolds in a variety of pharmaceutical and agrochemical agents. Herein, we report a highly efficient and practical method using DMF and its derivative for the [4+1] and [5+1] annulation reactions to prepare these heterocycles. This metal free reaction takes advantages of shelf stable DMF as solvent and carbon donor, imidazole chloride as a catalyst, the mild reaction condition tolerates a broad substrate range and substitutes. The prepared 3-unsubstituted 1,2,4-triazolo[3,4-a]pyridine and derivatives allow further introduction of a variety of functional group1 at 3-position.
- Liu, Lingfeng,Qiao, Chunhua,Shen, Bei,Xu, Yiwen
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- Formation of Pyrimidine-5-carboxaldehydes, 1-Aminoethylene-2,2-dicarboxaldehyde and 2-Amino-4-anilino-1,3,5-triazine from Triformylmethane and Amidines
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Triformylmethane (1) reacted with benzamidine, guanidine and S-methylisothiourea to give the corresponding 2-substituted pyrimidines-5-carboxaldehydes.However reactions of 1 with acetamidine (or formamidine) and phenylbiguanide gave the unexpected 1-aminoethylene-2,2-dicarboxaldehyde (5) and 2-amino-4-anilino-1,3,5-triazine (9), respectively.
- Takagi, Kaname,Bajnati, Abdelilah,Hubert-Habart, Michel
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p. 973 - 976
(2007/10/02)
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- Diuretics on the basis of N substituted 2,4 diamino s triazines by cyclisation of biguanides
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The structural class of 2,4 diamino s triazines (5) functioning as diuretics has become accessible by a novel preparatory procedure. The new synthesis is based on the aminomethinylating principle of s triazine (1), under the action of which biguanides (2) are cyclized to 5 passing through the intermediary states 3 and 4.
- Kreutzberger
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p. 1860 - 1862
(2007/10/04)
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