PYRAN DERIVATIVE AND MANUFACTURE

For the Contracting States BE, CH, LI, DE, FR, GB, IT 1. A pyran derivative of the formula la or lb see diagramm : EP0219091,P15,F1 where R**1 is C1 -C18 -alkyl or phenyl which is unsubstituted by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, R**2, R**3 and R**4 are each hydrogen, C1 -C6 -alkyl or phenyl which is unsubstituted or substituted by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, and A is a radical CH2-OR**5, where R**5 is C1 -C4 -alkyl or C2 -C8 -alkoxyalkyl or is bensyl which is unsubstituted substituted in the phenyl ring by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, or is tetrahydropyran-2yl, C1 -C4 -trialkylsilyl, formyl, C2 -C4 -alkylcarbonyl or benzoyl which is unsubstituted or substituted by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, or A is a radical CH(OR**6)2 , where R**6 is C1 -C4 -alkyl or C1 -C4 -alkyl or C1 -C4 -alkyl-carbonyl, or a radical CH(OR**6)2 which is unsubstituted or C1 -C4 -alkyl-substituted 1,3-dioxan-2-yl or unsubstituted or C1-C4-alkyl-substituted 1,3-dioxolan-2-yl, or A is a radical CO-OR**7, where R**7 is C1 -C4 -alkyl or phenyl which is unsubstituted or substituted by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, with the proviso that R**4 is not C1 -C4 -alkyl or unsubstituted or substituted phenyl when A is the radical CO-OR**7. For the Contracting State : AT 1. A process for the preparation of a pyran derivative of the formula la or lb see diagramm : EP0219091,P16,F1 where R**1 is C1 -C18 -alkyl or phenyl which is unsubstituted or substituted by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, R**2, R**3 and R**4 are each hydrogen, C1 -C6 -alkyl or phenyl which is unsubstituted or substituted by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, and A is a radical CH2-OR**5, where R**5 is C1 -C4 -alkyl or C2 -C8 -alkoxyalkyl or is benzyl which is unsubstituted or substituted in the phenyl ring by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, or is tetrahydropyran-2yl, C1-C4-trialkylsilyl, formyl, C2 -C4 -alkylcarbonyl or benzyl which is unsubstituted or substituted by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, or A is a radical CH(OR**6)2 , where R**6 is C1 -C4 -alkyl or C1 -C4 -alkyl or C1 -C4 -alkyl-carbonyl, or a radical CH(OR**6)2 which is unsubstituted or C1 -C4 -alkyl-substituted 1,3-dioxan-2-yl or unsubstituted or C1 -C4 -alkyl-substituted 1,3-dioxolan-2-yl, or A is a radical CO-OR**7, where R**7 is C1 -C4 -alkyl or phenyl which is unsubstituted or substituted by C1 -C4 -alkyl, C1 -C4 -alkoxy or halogen, with the proviso that R**4 is not C1