Furo coumarins

Ivie, G. W., R. C. Beier, and D. L. Holt. Analysis of the garden carrot (Daucus carota L.) for linear furo-coumarins (psoralens) at the sub parts per million level. J Agr Food Chem 1982 30(3) 413-416. 

The substitution pattern of TfOH-mediated electrophilic aminomethylation of psoralens (furo-coumarins) by V-(hydroxymethyl)phthalimide has been elucidated <85JHC73>. Multiple phthal-imidoylated adducts were obtained when a B-ring hydroxy or methoxy activating group was present, and these resisted simple cleavage with NH2NH2. However, this two-step procedure to aminomethyl group introduction worked well when the psoralens contained only methyl substituents. 

SYNS AMMOIDIN 6-HYDROXY-7-METHOXY-5-BENZOFURANACRYLIC ACID A-LACTONE MELADI-NIN MELADININE MELOXINE METHOXA-DOME METHOXSALEN 8-METHOXY-(FUR, NO-3, 2 il3.7-COUMARIN) 9-METHOXY-7H-FURO(3,2-g)BENZOPYRAN-7-ONE 8-METHOXY-2, 3, 6,7-FURO-COUMARIN 8-METHOXY-4, 5, 6,7-FUROCOUiMARIN 8-METHOXYPSOR. LEN 9-METHOXYPSORALEN 8-MOP 8-MP NCI-C55903 OXSORALEN OXY-PSORALEN PRORALONE-MOP... 

Photochemotherapy, which consists of oral (and sometimes topical) administration of psoralens (the furo-coumarins 5-methoxypsoralen, 8-methoxypsoralen, and trioxysalen) plus long-wave ultraviolet radiation, known as PUVA, is a well-established effective treatment for psoriasis, which has also been used for vitiligo (1), mycosis fungoides, alopecia areata, dyshidrotic eczema, atopic dermatitis, and certain other skin diseases. Guidelines for treatment have been recommended (2,3). 

Furan has been found to form oxetanes with a variety of carbonyl compounds, e.g., ketones,202-205 aldehydes,206 and ethyl cyanofor-mate.207 In most reactions the (2 + 2)-cycloaddition occurred specifically to give a 2,7 dioxabicyclo[3.2.0]hept-3-ene (175) rather than the 2,6-isomer (176). Only the addition of ethyl cyanoformate yielded mixtures of 175 and 176 (R = OEt and R2 = CN), in a ratio of 2 l.207 Two subsequent (2 + 2)-cycloadditions of benzophenone and furans have been reported to give two isomeric products, 177 and 178.205 Substituted furans yielded similar oxetanes.203 Benzo[ >]furans, furo-coumarins, and furochromones also proved to undergo (2 + 2)-cyclo-addition reactions with carbonyl compounds such as ketones, aldehydes, and quinones. Invariably one type of oxetane was formed (179).,37,u3 ,44 200-202 208,20, In the case of 2-methoxycarbonylbenzo[6)-furan, evidence has been provided that the oxetane was produced by addition of the excited triplet state of the olefinic reactant to the ground state of the ketone.208... 

Pathak, M.A., F. Daniels, and T.B. Fitzpatrick (1962). The presently known distribution of furo-coumarins (psoralens) in plants. J. Invest. Dermatol. 38, 225-239. 

Argentine plants. XXII. Heliettin, a new furo-coumarin from Helietta longifoliata Britt. Tetrahedron 23 1129-1137. 

As can be seen, the reaction between the anisyl derivative and the acetoacetate provided also tetrasubstituted furans. A subsequent demethylation cyclization delivered furo[3,4-c]coumarins in a moderate yield <06JHC 1699>. 

Dihydro-7-hydroxy-2R, 3R dimethyl-2-[4,8-imethyl-3 (E), 7 -nonadieny 1] -furo[3,2-C]coumarin ... 

Dihydro-7-hydroxy-2S, 3R -dimethyl-3-[4-methyl-5- (4-methy 1-2-furyl) -3(E)-pentenyl]-furo[3,2-C]coumarin Rt AOSZ... 

Dihydro- 7 -methoxy-2S, 3 R -dimethyl-2-[4,8-dimethyl-3(E),7-nonadien-6-onyl]-furo-[3,2-C]coumarin Rt AOSO... 

The photocyclodimerization of coumarin (2//-l-benzo[b]pyran-2-one) in direct and sensitized experiments is known to proceed rather inefficiently in the absence of Lewis acids and in better yields in their presence.42,43 In contrast, 2-quinolone (22, X = NH)44 or 1-thiocoumarin (2//-l-benzo[b]thiopyran-2-one 22, X = S)45 afford anti head-to-head dimers 23 on direct irradiation in very good yields. Psoralens (7//-furo[3,2-g][l]benzopyran-7-ones) usually exhibit a behavior similar to that of coumarins.46... 

Coumarinyloxy-2-butanones, obtained from suitable Bz-hydroxy-coumarins, can be dehydrated (with H2S04) to furocoumarins (e.g., 8-ethyl-7-hydroxy-4-methylcoumarin gives 9-ethyl-2,3,5-trimethyl-7.ff, furo[3,2-g][l]benzopyran-7-one (75).230... 

Unlike coumarin, chromone (206) undergoes efficient unsensitized photoaddition to tetramethylethylene, cyclopentene, ketene dimethyl acetal, and but-2-yne.180 The major product of such an addition to tetramethylene is the cis-fused cyclobutane derivative (207) the formation of the two minor products (208 and 209) is easily rationalized. Added benzophenone has no visible effect on this cycloaddition, which is therefore believed to involve the attack of triplet chromone on the ground-state alkene. Photoaddition to furo-chromones has also been studied,179 and the photosensitized cyclo-... 

In the presence of a ruthenium catalyst, 3-diazochroman-2,4-dione 716 undergoes insertion into the O-H bond of alcohols to yield 3-alkyloxy-4-hydroxycoumarins 717 (Equation 285) <2002TL3637>. In the presence of a rhodium catalyst, 3-diazochroman-2,4-dione 716 can undergo insertion into the C-H bond of arenes to yield 3-aryl-4-hydroxy-coumarins (Equation 286) <2005SL927>. In the presence of [Rh(OAc)2]2, 3-diazochroman-2,4-dione 716 can react with acyl or benzyl halides to afford to 3-halo-4-substituted coumarins (Equation 287) <2003T9333> and also with terminal alkynes to give a mixture of 477-furo[3,2-f]chromen-4-ones and 4/7-furo[2,3-3]chromen-4-ones (Equation 288) <2001S735>. 

Coumarins (chromen-2-ones) and furo- and pyrano-chromenones, mass spectra of ... 

Rhodium(II)-catalyzed reactions between diazosulfones and aldehydes yielded an entry to carbonyl ylides, which underwent inter- and intra-molecular cyclization reactions with dipolarophiles, such as alkynes and alkenes, to afford tetrasubstituted furans in modest to good yields <01SL646>. The rhodium(ll) acetate catalyzed reaction of 3-diazobenzopyran-2,4(3 -dione with terminal alkynes provided a mixture of 2-substituted furo[3,2-c]coumarin and furo[2,3-f ]coumarin, presumably through a formal [3+2] cycloaddition reaction <01S735>. Furo[3,2-c]coumarins were also produced from 4-hydroxycoumarins and a-haloketones via a tandem 0-alkylation-cyclization procedure <01TL3503>... 

The tosyloxylation of suitable ketones followed by heterocyclization has been utilized in the syntheses of the following heterocyclic systems 2-aroylbenzo[fe]furans [194], 3-aryl-5,6-dihydroimidazo[2,l- ][l,3]-thiazoles [194], 6-arylimidazo[2,l- ]thiazoles [195], (15 ,2/ )-indene oxide [196], 2-mercaptothiazoles [197], triazolo-[3,4-fc]-l,3,4-thiadiazines [198], dihydroindeno[l,2-e][l,2,4]triazolo[3,4- ][l,3,4]thiadiazines [199], furo[3,2-c]coumarins [200], 4,5-diarylisoxazoles [201], 2-substituted 4,5-diphenyloxazoles [202], quinoxaline [203], 3-carbomethoxy-4-arylfuran-2-(5//)-ones [204], thiazol-2(3//)-imine-linked glycoconju-gates [205] and other important heterocycles. 

Furo-2-pyridones. 1,4-Dimethyl -3- cyano -5-propargyl -6- hydroxy -2-pyridone dissolved in coned. H2SO4, and poured on ice after a few min. 5,6- (2-methyl-furano)-l,4-dimethyl-3-cyano-2-pyridone. Y 70%. F. e. s. J. Reisch, Arch. Pharm. 297, 754 (1964) furo[3,2-c]coumarins s. Arch. Pharm. 299, 457 (1966). 

The Rutaceae is one of the most interesting families in regard to alkaloid chemistry as well as the formation of fla-vonoids, mono-, sesqui-, and triterpenes, furocoumarins, and other secondary compounds (Waterman and Grundon, 1983). Many chemical features support the view that the Rutaceae is a distinct and homogenous group. Essential oils and coumarins are found in at least four subfamilies. Furo-quinoline alkaloids are essentially ubiquitous in the family, and acridones are common. 

C.-J. Lee, Y.-J. Jang, Z.-Z. Wu, W. Lin, Org. Lett. 2012, 14, 1906-1909. Preparation of functional phosphorus zwitterions from activated alkanes, aldehydes, and tributylphos-phine synthesis of polysubstituted furo[3,2-c]coumarins. 

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