In general, if the atoms that make up the ring contain heteroatoms, such rings become heterocycles, and organic compounds containing heterocycles are called heterocyclic compounds. An article called Pyrazine derivatives. I. 2-Hydroxy-3,6-dimethylpyrazine, published in 1947, which mentions a compound: 3400-55-3, Name is 2-Bromopriopionaldehydediethylacetal, Molecular C7H15BrO2, Reference of 2-Bromopriopionaldehydediethylacetal.
An examination of the methods for the synthesis of 2-hydroxypyrazines was undertaken with the object of synthesizing deoxyaspergillic acid (Part II). MeCH(NH2)CHO.HCl is a resinlike salt which could not be condensed with MeCHBrCOBr. MeCHBrCHO yields 63-4% MeCHBrCH(OEt)2 (I), b14 63-4°. I (70 g.) and 134 g. NH3 in 500 g. absolute EtOH, heated 7.5 h. at 125-30°, give 39% MeCH(NH2)CH(OEt)2 (II), b21 66°. II (7.45 g.) and 5.1 g. 4-methylmorpholine in 50 cc. CHCl3 at 0°, treated dropwise (30 min.) with 10.8 g. MeCHBrCOBr in 50 cc. CHCl3, with stirring for an addnl. hr. (during which the reaction mixture warmed to room temperature), give 11 g. α-(α-bromopropionylamino) propionaldehyde di-Et acetal, m. 56.5-7°; this could not be hydrolyzed to the aldehyde and could not be converted directly to 2-hydroxy-3,6-dimethylpyrazine (III). II (18 g.) in 10 cc. H2O, treated successively at 0° with 80 cc. concentrated HCl and 30 cc. EtSH, the mixture kept 24 h. at room temperature, poured into 200 cc. 40% NaOH and 500 g. ice, and the oil extracted with CHCl3, gives 73% α-aminopropionaldehyde di-Et mercaptal (IV), b3 105° (picrate, m. 153-4°). IV (19.5 g.), 15 g. butylpiperidine, and 50 cc. CHCl3 at 0°, treated dropwise with 25 g. MeCHBrCOBr in 50 cc. CHCl3, give 31 g. (crude) α-(α-bromopropionylamino) propionaldehyde di-Et mercaptal (V), m. 47-8°, slowly decompose on standing in air. V (3.14 g.) and 10 g. CdCO3 in 50 cc. EtOH and 10 cc. H2O, stirred 24 h. with 5.6 g. HgCl2 in 50 cc. EtOH, the filtrate saturated with NH3 at 0°, allowed to stand 48 h., the filtrate evaporated to dryness, and extracted with C6H6, give 250 mg. III, m. 210-11° (picrate, m. 181-5°). 2-Amino-3,6-dimethylpyrazine (20% yield) with NaNO2 in N HCl gives 60% III. 2-Aminopyrazine yields 30% 2-hydroxypyrazine, m. 187-8° [the brilliant yellow color observed by Weijland, et al. (C.A. 39, 3001.2) must be due to an impurity].
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Reference:
Piperazine – Wikipedia,
Piperazines – an overview | ScienceDirect Topics