Synthesis Of The Precursors Of Lower Fatty Acid And Pyrazine And The Application In Cigarettes

Oriental tobacco acts as a bridge between the aroma ofburley tobacco and Virginia tobacco in blended type cigarette.One of the remarkable characteristics of oriental cigarettesmoke is the abundant presence of lower fatty acids, such asisovaleric acid and B -methyl isovaleric acid, whichcontribute much to blended type cigarette smoke. Such volatilefatty acids in oriental tobacco smoke are reported to originatefrom the pyrolysis of glucose tetraester or sucrose tetraester.It was proposed that alkyl malonic acids could also pyrolyzeto form volatile fatty acids in tobacco smoke. Therefore,propyl malonic acid, isopropyl malonic acid, butyl malonic acidand s-butyl malonic acid were prepared and their structure wasconfirmed by 1HNMR 13CNMR and LC/MS. TG and DSC data of the fouralkyl malonic acids showed that they began to pyrolyze atapproximate 120C and lose their weight almost completelybelow 178C. To reveal the pyrolysis products of the alkylmalonic acids, five types of cigarettes were prepared. One isa control with no addition of alkyl malonic acid and the otherswith addition of 5% wt. of propyl malonic acid or isopropylmalonic acid or butyl malonic acid or s-butyl malonic acidrespectively. The five types of cigarettes were smoked and themainstream smoke of which was collected with ethanol respectively. GOMS results of the smoke extracts indicates that the alkyl malonic acids could pyrolyze to release valeric acid, isovaleric acid, hexanoic acid and B-methyl isovaleric acid respectively during smoking.2-(1' ,2' ,3' ,4' -Tetrahydroxybutyl)-5-(2 " ,3 " ,4 " -trihydroxybutyl) -pyrazine, a precursor of 2, 5-dimethylpyrazine and methylpyrazine, was synthesized by reaction of D-glucosamine hydrochloride with boronic acid. The product was characterized by LOMS, 13CNMR, and FT-ICRMS. It was found that the title compound added to tobacco was pyrolyzed to produce 2,5-dimethylpyrazine and methylpyrazine in cigarettes smoke, giving cigarettes better after-taste and aroma.