Claisen rearrangment of 3-(prop-2-ynylsulfanyl)-1,2,4-triazinone: A convenient route to 2-methylthiazolo[3,2-b][I,2,4]triazinone

590-59

<span style="font-size:19.5pt;mso-bidi-font-size:12.5pt">A synthetic route to 2,6-dimethylthiazolo <span style="font-size:19.5pt;mso-bidi-font-size:12.5pt;font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";mso-ansi-language:EN-US;mso-fareast-language: EN-US;mso-bidi-language:AR-SA">{3,2-<i style="mso-bidi-font-style:normal">a</i>]pyrinnidin-7-one</span></span>

216-217<span style="font-size:15.5pt;mso-bidi-font-size:8.5pt; font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">1N-Propargyl-6-metbylthiouracil 2 <span style="font-size: 16.0pt;mso-bidi-font-size:9.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">has <span style="font-size:15.5pt; mso-bidi-font-size:8.5pt;font-family:" times="" new="" roman";mso-fareast-font-family:="" "times="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa"="">been prepared in good yield from 6-methylthiouracil, hexametbyl disilazane and (NH4)2<span style="font-size:13.5pt;mso-bidi-font-size:6.5pt;font-family:HiddenHorzOCR; mso-hansi-font-family:" times="" new="" roman";mso-bidi-font-family:hiddenhorzocr;="" mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">SO4 followed by treatment with propargyl bromide. Compound 2 on acid catalyzed cyclization yields 2,6- dimethylthiazolo[3,2-a ]pyrimidin-7-one 4.</span