TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (disclosed): Benzaldehyde compound of formula (II) and pyridine derivative of formula (III) are reacted in the presence of catalyst and mixed solvent at -50 degrees C to 50 degrees C under inner gas atmosphere to obtain alcohol compound of formula (IV). Alcohol compound (IV) is reacted with ketone compound of formula (Va) or dialkoxy compound of formula (Vb) and cyclized in presence of acidic catalyst, dehydrating agent and mixed solvent at 100 degrees C from room temperature to obtain nitrogen-containing heterocyclic compound (I).Z'=amino or hydroxyl;Ra=H or esterified hydroxyl, Z'and Ra optionally form cyclic structure;M=leaving group;andR=methyl or ethyl. Preferred Definitions:    R5,R6=group which forms aromatic ring and one group.    ACTIVITY - Fungicide. Emulsion of nitrogen-containing heterocyclic compound (e.g. 1,2-dihydro-2,2-dimethyl-4-(3-quinolyl)-4H-3,1-benzoxazine) was applied to apple seeding. Then, the apple seedling was infected with conidium of Venturia inaequalis and maintained for two weeks at 20 degrees C in a brightness and dark cycle for every 12 hours. The disease rate was determined by appearance of symptoms. The fungal infection prevention effect of nitrogen-containing heterocyclic compound was found to be 75% or more.    MECHANISM OF ACTION - None given.    ADMINISTRATION - The nitrogen-containing heterocyclic compound is administered at a dosage of 1-1000 (preferably 10-100) g/hectare by dispersion on crops and soil.    SPECIFIC COMPOUNDS - 344 nitrogen-containing heterocyclic compounds are disclosed for e.g. 1,2-dihydro-2,2-dimethyl-4-(3-quinolyl)-4H-3,1-benzoxazine (Ia), 3- (8-fluoro-2,2-dimethyl-4H-benzo(1,3)dioxin-4-yl)-quinoline, 2-chloro-5-(2,2-dimethyl-4H-benzo(1,3)dioxin-4-yl)-3-methylpyridine, 8-fluoro-3-(8-fluoro-2,2-dimethyl-4H-benzo(1,3)dioxin-4-yl)-quinoline and 8-fluoro-3-(8-chloro-2,2-dimethyl-4H-benzo(1,3)dioxin-4-yl)-quinoline.    EXAMPLE - Toluene sulfonic acid monohydrate (13.5 mg) was added to toluene-acetone solution of (2-aminophenyl)-quinoline-3-yl-methanol (0.18 g), and stirred at room temperature for 24 hours. The reaction solution was added to diethyl ether and saturated sodium hydrogen carbonate aqueous solution. The organic layer was washed and dried to produce 1,2-dihydro-2,2-dimethyl-4-(3-quinolyl)-4H-3,1-benzoxazine. The obtained compound (in wt.pts) (40), clay (48), dioctyl sulfosuccinate sodium salt (4) and sodium lignin sulfonate salt (8) were mixed and pulverized to obtain water-dispersible powder.