Description General description Diastereoselectivity in [4+2] cycloaddition of 1-methoxy-2-methyl-3-(trimethylsiloxy)-1,3-pentadiene with 5-nitro-2-thiophenecarboxaldehyde was investigated. Application 5-Nitro-2-thiophenecarboxaldehyde was used in preparation of 2, 3-dihydro-2-(5-nitro-2-thienyl) quinazolin-4-(1H)-ones and various novel oxime ether derivatives, anti-protozoan agents. Packaging 5, 25 g in glass bottle