the new hydroxybiphenyl compounds of the general formula ( i ) can be obtained , for example , in the following manner . the &# 34 ; tokoboku &# 34 ; is extracted with water or methanol at room temperature and the extract is then concentrated . the thus concentrated extract is partitioned between water and ethyl acetate and the ethyl acetate layer is concentrated and the concentrate is then subjected to column chromatography on silica gel . elution is carried out using solvents such as hexane , benzene , acetone and ethyl acetate , or mixtures of such solvents in varied ratios . the appropriate eluates are further subjected to column chromatography on silica gel , alumina and / or sephadex lh - 20 , and the column is developed and eluted with solvents such as methanol , hexane : benzene , hexane : acetone , benzene : acetone , benzene : ethyl acetate , chloroform : acetone and chloroform : methanol . the compounds of the invention are useful as pharmaceuticals or intermediates therefor , in particular as anti - allergic agents . the following examples illustrate the preparation and physical properties of some of the compounds of the present invention . the structures of the compounds shown in the examples were identified , in any case , on the basis of mass spectra , elementary analysis , ir spectra , uv spectra and nmr ( pmr ) spectra . four kg of &# 34 ; tokoboku &# 34 ; is ground and the ground product subjected twice to extraction with 9 l of water at room temperature for 24 hours . the extracts are combined and concentrated until 600 g of an extract is obtained . this extract is dissolved in 2 l of water and partitioned three times between ethyl acetate and the water . the ethyl acetate layer is concentrated until 300 g of the concentrate ( i . e . extract ) is obtained . the concentrate is subjected to column chromatography on 500 g of silica gel , using as eluent solvent mixtures of benzene : ethyl acetate in increasing ratios of from 1 : 0 to 3 : 1 . the eluates are collected as benzene , benzene : ethyl acetate ( 50 : 1 ), benzene : ethyl acetate ( 20 : 1 ), and benzene : ethyl acetate ( 3 : 1 ) eluates , each being a 100 ml fraction . the solvent is distilled off from the benzene eluate fraction and the residue subjected to column chromatography on 50 g of alumina . the column is eluted with hexane : benzene ( 3 : 1 ) to give 400 mg of the compound of the following formula ( ii ) as a colorless oil . ## str7 ## elementary analysis ( for c 28 h 34 o 2 ): calculated (%): c , 83 . 53 ; h , 8 . 51 ; o , 7 . 96 . found (%): c , 83 . 62 ; h , 8 . 31 ; o , 8 . 07 . specific rotation : [ α ] d 20 - 7 . 6 ° ( c = 1 . 67 , chcl 3 ). nmr ( pmr ) spectrum ( δ in cdcl 3 ): 0 . 80 ( 3h , s ), 0 . 83 ( 3h , s ), 0 . 87 ( 3h , s ), 0 . 80 - 2 . 45 ( 7h , m ), 3 . 36 ( 4h , m ), 4 . 38 ( 1h , dd , j = 2 . 5 hz , 9 hz ), 4 . 90 - 5 . 20 ( 4h , m ), 5 . 75 - 6 . 23 ( 2h , m ), 6 . 28 ( oh , br . s ), 6 . 80 - 7 . 25 ( 6h , m ). the solvents are distilled off from the benzene : ethyl acetate ( 50 : 1 ) eluate fraction obtained in example 1 . the residue is subjected first to column chromatography on 50 g of alumina using methanol as eluent , and then to column chromatography on 100 g of silica gel using as eluent hexane : acetone ( 10 : 1 ) to give 200 mg of the compound of the following formula ( iii ) as a colorless oil . ## str8 ## elementary analysis ( for c 28 h 34 o 2 ): calculated (%): c , 83 . 53 ; h , 8 . 51 ; o , 7 . 96 . found (%): c , 83 . 75 ; h , 8 . 14 ; o , 8 . 11 . specific rotation : [ α ] d 20 - 97 . 0 ° ( c = 0 . 69 , chcl 3 ). nmr ( pmr ) spectrum ( δ in cdcl 3 ): 0 . 83 ( 3h , d , j = 6 hz ), 0 . 89 ( 3h , d , j = 6 hz ), 1 . 72 ( 3h , br . s ), 1 . 20 - 2 . 20 ( 6h , m ), 3 . 30 ( 2h , d , j = 6 . 5 hz ), 3 . 42 ( 2h , d , j = 6 . 5 hz ), 3 . 50 ( 1h , m ), 4 . 92 - 5 . 30 ( 4h , m ), 5 . 41 ( 1h , br . s ), 5 . 78 - 6 . 25 ( 2h , m ), 6 . 80 - 6 . 90 ( 3h , m ), 7 . 18 - 7 . 37 ( 2h , m ). the solvents are distilled off from the benzene : ethyl acetate ( 20 : 1 ) eluate fraction obtained in example 1 . the residue is subjected first to column chromatography on 50 g of sephadex lh - 20 using benzene : acetone ( 20 : 1 ) as eluent and then to column chromatography on 100 g of silica gel using chloroform : acetone ( 50 : 1 ) as eluent . the eluent is distilled off from a fraction of the chloroform acetone ( 50 : 1 ) eluate , which fraction was confirmed by thin layer chromatography to contain a single constituent . the residue is crystallized from benzene to give 400 mg of the compound of the following formula ( iv ): ## str9 ## as light yellow needles , m . p . 135 °- 136 ° c ., as well as 400 mg of the compound of the following formula ( v ): ## str10 ## as light yellow needles , m . p . 153 °- 157 ° c . the compounds of the formulas ( iv ) and ( v ) were named magnaldehyde a and magnaldehyde b , respectively : elementary analysis ( for c 18 h 16 o 3 ): calculated (%): c , 77 . 12 ; h , 5 . 75 ; o , 17 . 13 . found (%): c , 77 . 14 ; h , 5 . 81 ; o , 17 . 05 . specific rotation : [ α ] d 20 ± 0 ° ( c = 1 . 20 , chcl 3 ). uv spectrum ( λ max meoh nm ): 373 ( ε = 26 , 000 ), 330 ( ε = 28 , 000 ). ir spectrum ( ν max chcl . sbsp . 3 cm - 1 ): 1675 , 1625 , 1605 , 1580 . nmr spectrum ( δ in acetone - d 6 ): 3 . 35 ( 2h , d , j = 6 . 5 hz ), 4 . 90 - 5 . 20 ( 2h , m ), 5 . 80 - 6 . 20 ( 1h , m ), 6 . 65 ( 1h , dd , j =[ hz , 16 hz ), 6 . 90 - 7 . 65 ( 6h , m ), 7 . 62 ( 1h , d , j = 16 hz ), 9 . 61 ( 1h , d , j = 8 hz ). elementary analysis ( for c 18 h 16 o 3 ): calculated (%): c , 77 . 12 ; h , 5 . 75 ; o , 17 . 13 . found (%): c , 77 . 15 ; h , 5 . 79 ; o , 17 . 06 . specific rotation : [ α ] d 20 ± 0 ° ( c = 1 . 00 , chcl 3 ). uv spectrum ( λ max meoh nm ): 324 ( ε = 33 , 000 ), 284 ( ε = 40 , 000 ) . ir spectrum ( ν max chcl . sbsp . 3 cm - 1 ): 1675 , 1625 , 1605 , 1580 . nmr spectrum ( δ in acetone - d 6 ): 3 . 44 ( 2h , m ), 4 . 90 - 5 . 23 ( 2h , m ), 4 . 85 - 5 . 24 ( 1h , m ), 6 . 67 ( 1h , dd , j = 8 hz , 16 hz ), 6 . 92 ( 1h , d , j32 8 hz ), 7 . 03 ( 1h , d , j = 8 hz ), 7 . 33 ( 1h , dd , j = 2 . 5 hz , 8 hz ), 7 . 37 ( 1h , br . s ), 7 . 51 ( 1h , dd , j = 2 . 5 hz , 8 hz ), 7 . 60 ( 1h , d , j = 2 . 5 hz ), 7 . 60 ( 1h , d , j = 16 hz ), 9 . 62 ( 1h , d , j = 8 hz ). the eluent is distilled off from the benzene : ethyl acetate ( 3 : 1 ) eluate fraction obtained in example 1 . the residue is subjected first to column chromatography on 100 g of silica gel using benzene : ethyl acetate ( 20 : 1 ) as eluent and then to column chromatography on 100 g of silica gel using as eluent chloroform : methanol ( 150 : 1 ) and chloroform : methanol ( 20 : 1 ). the eluent is distilled off from the eluate fraction which was found to contain a single ingredient by thin layer chromatography . there are thus obtained 200 mg of the compound of the following formula ( vi ): ## str11 ## as a colorless oil as well as 300 mg of a yellow solid product . the yellow solid product is recrystallized from benzene : chloroform to give 200 mg of the compound of the formula ( vii ): ## str12 ## as pale yellow needles , m . p . 99 °- 100 ° c . the compounds of the formulas ( vi ) and ( vii ) were named magnotriol la and magnotriol b , respectively . elementary analysis ( for c 15 h 14 o 3 ): calculated (%): c , 74 . 37 ; h , 5 . 82 ; o , 19 . 81 . found (%): c , 74 . 45 ; h , 5 . 78 ; c , 19 . 77 . specific rotation : [ α ] d 20 ± 0 ° ( c = 1 . 10 , chcl 3 ). nmr spectrum ( δ in acetone - d 6 ): 3 . 35 ( 2h , m ), 4 . 90 - 5 . 20 ( 2h , m ), 5 . 29 - 3 . 20 ( 1h , m ), 6 . 75 ( 1h , dd , j = 3 hz , 9 hz ), 6 . 79 ( 1h , d , j = 3 hz ), 6 . 84 ( 1h , d , j = 9 hz ), 6 . 94 ( 1h , d , j = 9 hz ), 7 . 05 ( 1h , dd , j = 2 . 5 hz , 9 hz ), 7 . 11 ( 1h , br . s ). elementary analysis ( for c 15 h 14 o 3 ): calculated (%): c , 74 . 37 ; h , 5 . 82 ; o , 19 . 81 . found (%): c , 74 . 47 ; h , 5 . 81 ; o , 19 . 72 . nmr spectrum ( δ in acetone - d 6 ): 3 . 40 ( 2h , m ), 4 . 90 - 5 . 20 ( 2h , m ), 5 . 83 - 6 . 28 ( 1h , m ), 6 . 65 ( 1h , dd , j = 3 hz , 9 hz ), 6 . 80 ( 1h , d , j = 3 hz ), 6 . 84 ( 1h , d , j = 9 hz ), 6 . 96 ( 1h , d , j = 9 hz ), 7 . 28 ( 1h , dd , j = 2 . 5 hz , 9 hz ), 7 . 33 ( 1h , br . s ). these six new hydroxybiphenyl compounds are all obtained from the ethyl acetate extract , whose anti - allergic activity was determined by the following experimentation . experiments were carried out in accordance with the asherson and ptak method for contact and delayed hypersensitivity in mice . thus , male ddy mice , 8 - 10 weeks of age , were used and 0 . 1 ml of a 7 % solution of picryl chloride in a carrier such as ethanol was applied to the abdomen of groups of ten animals each . seven days after the sensitization , 0 . 02 ml of a 1 % solution of picryl chloride in a carrier such as olive oil was applied to both ear lobes of each animal to induce contact dermatitis . twenty four hours after the application , the thickness of the ear lobes was measured with a dial thickness guage ( ozaki seisaku - sho ). the values obtained by subtracting , from the thus measured thickness , the thickness of the ear lobes before the induction were used as a measure of swelling caused by the induced contact dermatitis . the crude drug extracts to be tested , i . e . the aqueous extract , the ethyl acetate extract and etoac # 2 * extract , were each administered orally with a suitable carrier therefor at a dose of 50 mg / kg 16 hours after the induction of the contact dermatitis . the results are shown in the table . table______________________________________crude drug extract dose swelling inhibitionto be tested ( mg / kg ) (× 10 . sup .- 3 cm ) (%) ______________________________________control 50 5 . 22 ± 1 . 086aqueous extract 50 3 . 69 ± 0 . 934 29 . 3ethyl acetate extract 50 3 . 49 ± 0 . 762 33 . 1etoac # 2 * extract 50 2 . 49 ± 0 . 431 52 . 3______________________________________ * benzene : ethylacetate ( 3 : 1 ) eluate fraction the results shown in the table show that the ethyl acetate extract has a greater inhibitory effect on contact dermatitis than the aqueous extract . thus , they demonstrate that the six new hydroxybiphenyl compounds mentioned above possibly have an inhibitory effect on contact dermatitis .