'Department of Organic Chemistry, Faculty of Natural Sciences, Komenský University, Bratislava. Received 16 December 1980

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1 Synthesis of halo and nitro derivatives of -(l-naphthyloxymethylene)phthalide and -(-naphthyloxymethylene)phthalide a M. LCOV and b M. BRONDOŠ 'Department of Organic Chemistry, Faculty of Natural Sciences, Komenský University, 8 Bratislava b Chemosvit, 9 Svit Received 6 December 98 Preparation of halo and nitro derivatives of -naphthyloxymethylenephthalides by Gabriel modification of Perkin synthesis from phthalic anhydride and the properly substituted naphthyloxyacetic acid as well as by nitration and halogenation of unsubstituted E and Z isomers of -naphthyloxymethylenephthalides is dealt with. Some of the prepared derivatives have been proved to inhibit plant growth. Описаны методики получения галоген- и нитропроизводных -нафтилоксиметиленфталидов модификацией синтеза Перкина по Габриелу из фталангидрида и соответствующей замещенной нафтилоксиуксусной кислоты и нитрованием и галогенированием незамещенных E и Z изомеров -нафтилоксиметиленфталидов. Некоторые из полученных производных ингибируют рост растений. Synthesis of halo and nitro derivatives of -naphthyloxymethylenephthalides was carried out in order to examine the optimal conditions and suitability of the method for the preparation of new biologically active compounds. It is known that aryloxymethylenephthalides and their derivatives show significant biological activity, for instance, they inhibit plant growth [,] and stimulate the growth of roots and leaves []. These compounds have been reported to possess also insecticidal properties, such as inhibition of juvenile hormones [, ]. To prepare the products we used the proved method for the preparation of phthalides, i.e. the Gabriel modification of Perkin synthesis. We started from phthalic anhydride and suitably substituted - and -naphthyloxyacetic acid [6]. This method led, as described in Experimental, to unambiguous results also in the case of preparation of substituted -(l-naphthyloxymethylene)phthalides and -(-naphthyloxymethylene)phthalides. The more stable and less soluble Z isomer is present in the product in higher amount. The E isomer is present in smaller amount (about % of the Z isomer) and its isolation is complicated as the reaction is accompanied by formation of Chem. zvesti 6 () (98)

2 M. LÁCOVÁ, M. BRONDOŠ by-products, dark-brown pasty compounds, which are similarly soluble as the E isomer. The reactions of naphthyloxyacetic acids substituted by halogen or nitro group must be carried out at lower temperatures (by about C) than those of the unsubstituted ones. The second method used for the preparation of new derivatives of phthalides was the halogenation and nitration of -(l-naphthyloxymethylene)phthalides and -(-naphthyloxymethylene)phthalides. We have found that this method did not lead to uniform results. Similar conclusions have been reported in [79]. Phthalides, according to the papers mentioned above where nitration and halogenation of benzalphthalide, -(l-naphthylmethylene)phthalide, and -(-naphthylmethylene)phthalide have been described, can give substitution and addition products along with products of simultaneous substitution and addition. The authors have found a dependence of the reaction products on the structure of the starting phthalide. In nitration and halogenation of -naphthyloxymethylenephthalides we focused our attention on the study of the effect of reaction conditions and structure of the phthalide isomer on the formation of a certain type of the reaction product. In reactions with electrophile agents we used the isolated E and Z isomers. We have found that, under the conditions described in Experimental, the E and Z isomers of the phthalides investigated behaved differently. The Z isomer of -(-naphthyloxymethylene)phthalide by bromination afforded a substitution- -addition product while by nitration an addition product only. The E isomer of -(-naphthyloxymethylene)phthalide reacted with both bromine and nitric acid in addition manner only. Bromination and nitration of the E isomer of -(l-naphthyloxymethylene)phthalide resulted in addition-substitution product and the Z isomer gave an addition product only (Scheme ). From the obtained experimental data it can be assumed that the investigated phthalides gave by nitration with nitric acid and by bromination with elemental bromine predominantly products of addition to the double bond. We failed to identify the product of substitution on the naphthalene ring only as described by the authors investigating similar reactions with phthalide derivatives based on naphthylacetic acids in [7, 8]. The difference between both types of the starting compounds lies in the oxygen bridge which joins the phthalide cycle with the naphthalene ring. We assume that the difference in the reactivity of both types of compounds is a result of steric release in the region of the double bond by oxygen bridge, whiph enables a higher addition rate to the double bond and simultaneously also the stability of the isomer. In the reaction with the JE isomer of -(l-naphthyloxymethylene)phthalide we supposed the substitution in the position and with the Z isomer of -(-naphthyloxymethylene)phthalide in the position of the naphthalene ring. We proved this suggestion by comparison of the substitution-addition product with the products of bromination of -(-bromo-l-naphthyloxy- 6 Chem. zvesti 6 {) (98)

3 HLO ND NITRO DERIVTIVES О II :oi"> x I xс-н I. ť> --NO o NСH i W > H /CN O. ' «Br -HBr Scheme methylene)phthalide and -( -bromo--naphthyloxymethylene)phthalide (Table ) obtained by direct synthesis. The compounds mentioned above had identical melting points and i.r. spectra. With some of the prepared compounds inhibition of plant growth has been observed. Herbicidal tests (carried out according to [] using,-dichlorophenoxyacetic acid as standard) are presented in Table. Noticeable activity has been found with the compound V (Table ). Chem. zvesti 6() (98) 7

4 Table Characteristics of -(X-- and -(X-l-naphthyloxymethylene)phthalides Compound Formula M Calculated/found %C %H %N % Halogen M.p., C Solvent v(c=) cm" í ÍÍ III IV V VI VII -C -a l-br -Br - - -N С9НОСЛ С^НцОзСЛ С9НГ С9НГ C9HI cl 9 Hn I C 9 H N ; CHCOOH 86 CHCOOH 66 Benzene 77 Benzene ecu 77 CHCOOH 7 (CH ) SO N v,(n ) 6 v M (N ) 7

5 ТаЫе Herbicidal activity of -naphthyloxymethylenephthalides Test objects Compounds Zea mays Bera vulgaris Sinapis alba Fagopyrum vulgare Tnticum aestivum Pisum sativum в I II IV V M -(-Naphthyloxymethylene)phthalide. E isomer [6] -(-Naphthyloxymethylene)phthalide io Z isomer [6] Standard Concentration kg/ha; concentration kg/ha, degree of inhibition, % inhibition.

M. LÁCOVÁ, M. BRONDOŠ Experimental Infrared spectra were measured on a UR- spectrophotometer (Zeiss, Jena) in the region of 7 cm -. The apparatus was calibrated by polystyrene foil.

6 M. LÁCOVÁ, M. BRONDOŠ Experimental Infrared spectra were measured on a UR- spectrophotometer (Zeiss, Jena) in the region of 7 cm -. The apparatus was calibrated by polystyrene foil. The samples were prepared in the form of suspension in paraffin oil (Nujol). The spectrum of Nujol has been compensated. -(-X-l-Naphthyloxymethylene)phthalide (X = Cl,Br,N ) The mixture of remelted phthalic anhydride ( g;. mol), -X-l-naphthyloxyacetic acid (.7 mol), and remelted potassium acetate (. g;. mol) was stirred and heated for h at 89 C. The hot reaction mixture was poured into % sodium hydrogen carbonate ( cm ). fter h staying the insoluble precipitate was filtered off and dried. The precipitate was dissolved in cold ethanol ( cm ). The insoluble portion was filtered off and crystallized several times from benzene giving the Z isomer. The alcoholic solution was evaporated to half volume, diluted with water and the formed precipitate was crystallized from the mixture of ethanolwater (:) (E isomer). The compounds prepared by this procedure are presented in Table. Nitration of E and Z isomers of-(l-naphthyloxymethylene)phthalide To the nitration mixture, prepared from glacial acetic acid ( cm ) and concentrated nitric acid ( cm ), the appropriate isomer of phthalide ( g;. mol) was added portionwise under stirring at C. fter min reaction the yellow precipitate was filtered off, dried, and crystallized from benzene. The product from Z isomer obtained in 9% yield had m.p. 6 C (sublimation). For C 9 H 8 N (96.) calculated: 7.9% C,.% H, 7.6% N; found: 7.8% C,.9% H, 6.8% N. IR spectrum (v/cirr ): v(c=) 778, v(coc) 7, vjn ), v.(n ). The product from E isomer obtained in 98% yield by crystallization from the mixture of ethanolwater (:) were yellow crystals of melting point 88 C. For С 9 Н п ^ (.) calculated:.7% C,.9% H, 9.% N; found:.9% C,.6% H, 9.7% N. IR spectrum (v/cm" ): v(c=) 78, v(cоc) 66, v M (N ), v e (N ) 8. Bromination o f E and Z isomers of -(l-naphthyloxymethylene)phthalide Procedure To phthalide ( g) dissolved in chloroform ( cm ) bromine ( g) in chloroform ( cm ) was added dropwise under vigorous stirring at C. CTiem. zvesti 6 () (98)

7 HLO ND NITRO DERIVTIVES Procedure The reaction was carried out in chlorobenzene under reflux. From Z isomer (procedure ) the precipitate, formed after h, was filtered off and crystallized from benzene. Yield 9%, m.p. 99 C. From Z isomer (procedure B) the yield of the product was 8%, m. p. 99 C. For C 9 Hi Br (7.) calculated:.9% C,.67% H,.6% Br; found:.8% C,.6% H,.% Br. IR spectrum (v/спг ): v(c=) 7, v(co-c). From E isomer (procedure ) the product was obtained by evaporation of the reaction mixture to / volume. fter cooling the formed precipitate was crystallized from acetic acid. Yield 86%, m.p. 666 C. For C 9 H n Br (7.) calculated:.% C,.8% H,.% Br; found:.% C,.9% H,.7% Br. IR spectrum (v/cnr ): v(c=) 7, v(cоc). Bromination of E and Z isomers of-(-naphthyloxymethylene)phthalide The precipitate obtained from Z isomer by the previous procedure was crystallized from acetic acid. M.p. 996 C, yield 8%. For С 9 Н п гз (7.) calculated:.% C,.8% H,.% Br; found:.% C,.9% H,.% Br. IR spectrum (v/cnr ): v(c=) 766, v(cоc) 6. The product obtained from Z isomer by the procedure was crystallized from benzene. Yield 7%, m.p. 8 C. For C 9 Hi Br (7.) found:.6% C,.% H,.9% Br. IR spectrum (v/спг ): v(c=) 7, v(cоc). Nitration of E and Z isomers of-(-naphthyloxymethylene)phthalide To the nitration mixture, prepared from glacial acetic acid ( cm ) and nitric acid ( cm ), phthalide ( g) was added in small portions under stirring for min at C. fter min the yellow precipitate was filtered off, dried, and crystallized from benzene. The product obtained from Z isomer in 8% yield had melting point 6 C. For C 9 H 8 N (96.) calculated: 7.9% C,.% H, 7.6%N; found: 7.9% C,.% H, 6.7% N. IR spectrum (v/спг ): v(c=) 7, v(c-o-c), v^noj), v s (N ) 6. The product from E isomer was obtained in 8% yield and had melting point 68 C (benzene). For C 9 H 8 N (96.) calculated: 7.9% C,.% H, 7.6% N; found: 7.% C,.6% H, 6.8% N. IR spectrum (v/спг ): v(c=) 7, v(cоc), v a (N ), v s (N ). cknowledgements. We thank Ing. J. Synak (Research Institute of grochemical Technology, Bratislava) for the results ofherbicidal tests and Ing. E. Greiplova (Institute of Chemistry, Komenský University, Bratislava) for elemental analysis. Chem. zvesti 6 () (98)

8 M. LÁCOVÁ, M. B RONDOS References. Lácová, M. and Priehradný, S., Czech... Lácová, M. and Synak, J., Czech. ppl Hlásniková,., unpublished results.. Paulovová, J., Paulov, Š., and Lácová, M., Biológia (Bratislava), 7 (978).. Lácová, M., Pauloy, Š., and Paulovová, J., Czech. ppl Furdík, M., Lácová, M., Livař, M., and Hrivnák, J., Chem. Zvesti, 8 (966). 7. Furdík, M. and Hrnčiar, P., Chem. Zvesti, (96). 8. Furdík, M. and Hrnčiar, P., Chem. Zvesti, 6 (98). 9. Lácová, M., Volná, F., Greiplová, E., and Hrnčiar, P., Chem. Zvesti, 9 (97). Translated by. Kardošová Chem. zvesti 6 () (98)

Q1. Ammonia is used in the production of fertilisers. The flow diagram shows the main stages in the manufacture of ammonia.

Q1. Ammonia is used in the production of fertilisers. The flow diagram shows the main stages in the manufacture of ammonia. Study the flow diagram and then answer the questions. (a) What is the purpose