2-Furyl carbonates

The preparation of furyl phosphorodichioridate is based upon a method to prepare 2-chlorofuran (16% yield, Hormi, Nasman unpublished). Later the preparation was extended to a general method to prepare furyl esters from carboxylic acid chlorides lacking a-hydrogens and alkyl furyl carbonates from primary (other than methyl) and secondary alkyl chloroformates. Phosphoryl chloride was the only acid chloride except carbon analogues found to give a furyl ester by the amine-catalyzed reaction. 

Ethylene, /3-(dimethylamino)-nitro-in pyrrole synthesis, 4, 334 Ethylene, dithienyl-in photochromic processes, 1, 387 Ethylene, furyl-2-nitro-dipole moments, 4, 555 Ethylene, l-(3-indolyl)-2-(pyridyl)-photocyclization, 4, 285 Ethylene, l-(2-methyl-3-indolyl)-l,2-diphenyl-synthesis, 4, 232 Ethylene, (phenylthio)-photocyclization thiophenes from, 4, 880 Ethylene carbonate C NMR, 6, 754 microwave spectroscopy, 6, 751 photochemical chlorination, 6, 769 synthesis, 6, 780 Ethylene oxide as pharmaceutical, 1, 157 thiophene synthesis from, 4, 899 Ethylene sulfate — see 2,2-dioxide under 1,3,2-Dioxathiolane... 

Alfuzosin (91) is a prazosin-like hypotensive adrenergic a-1 receptor blocker with the special structural feature that two carbons have been excised conceptually from the piperazine ring normally present in this series. Following the usual sequence for this series, reaction of 4-amino-2-chloro-7-dimethoxyquinazoline (89) with the tetrahydro-2-furyl amide of 3-methylaminopropyla-mine (90) gives alfuzosin (91) [25], Alfuzosin is claimed to cause less orthostatic hypotention (dizziness or fainting upon sudden rising) than prazosin. 

We owe to Kato and his colleagues a considerable advance in furan copper reagents. They have demonstrated the formation of the lithium di(3-furyl) cuprate species 87 which is highly reactive and possesses hard properties that suit it to reaction at hard centers, mainly carbonyl carbon.223 The reagent is easily prepared in situ from 3-furyllithium and Cu2I2. Simple copper derivatives do not react with ketones, but this cuprate reacts well and quantitatively with acid chlorides. It also reacts well with some epoxides (oxirans). Moreover, there is another form prepared in the presence of... 

W=X is N=N or C=N, never if it is C=C. The ring stability of 3-furyl-carbenes conforms with this rule. Ring opening is again the main reaction in a biradical which is generated by extruding carbon dioxide from a lactone at 675°C and which then collapses to an acetylenic ketone.277... 

Like most aryl halides, furyl halides and furyl triflates have been coupled with a variety of organostannanes including alkenyl, aryl, and heteroaryl stannanes in the presence of catalytic palladium. Carbamoylstannane 66 was prepared by treating lithiated piperidine with carbon monoxide and tributyltin chloride sequentially. The Stille reaction of 66 and 3-bromofuran then gave rise to amide 67 [61]. In another example, lithiation of 4,4-dimethyl-2-oxazoline followed by quenching with MesSnCl resulted in 2-(tributylstannyl)-4,4-dimethyl-2-oxazoline (68) in 70-80% yield [62], Subsequent Stille reaction of 68 with 3-bromofuran afforded 2-(3 -furyl)-4,4-dimethyl-2-oxazoline (69). 

Treatment of a mixture of a chloro oxime 177 (R = H, Ph, 4-BrCgH4 or 2-furyl) and a diene (cyclopentadiene or 2,3-dimethylbuta-l,3-diene) with solid sodium carbonate results in the formation of a dihydrooxazine, the intermediate nitrosoalkene 178 having reacted as a heterodiene (equation 98)94. In contrast, l,l-dichloro-2-nitrosoethene and cyclopentadiene yield the epoxyepimine 179 (equation 99)94. 

Electrolysis of 2-furoyl chloride at mercury affords mainly l,2-di(2-furyl)ethene-l,2-diol di(2-furoate) however, an interesting pair of minor products are l,2-di(2-furyl)-2-hydroxy-3-cyanopropanone and 3-(2-furyl)acryloni-trile, in which a fragment of the solvent (acetonitrile) is incorporated [78]. When 2,4,6-trimethylbenzoyl chloride is reduced at carbon or mercury cathodes in acetonitrile, the major products are 2,4,6-trimethylbenzaldehyde and 3-(2,4,6-trimethylphenyl)acrylonitrile,... 

A few substances were collected in bags. These analytes are generally very volatile and weakly sorbed, even on charcoal. They included carbon monoxide, carbon dioxide, sulfur hexafluoride, sul-furyl fluoride, methyl acetylene, and methyl acetylene/propadiene mixture. 

Aromatic species include the neutral molecules pyrrole, furan and thiophene (1 Z = NH, O, S) and the pyrrole anion (2). The radicals derived from these rings are named pyrryl, furyl and thienyl. The 2-furylmethyl radical is called furfuryl. Compounds in which two pyrrole nuclei are joined by a CH2 group are called dipyrromethanes when the linkage is by a CH group, they are named dipyrromethenes . The 2- (3) and 3-pyrrolenines (4) are isomeric with the pyrroles, but are nonaromatic as the ring conjugation is broken by an. s/r -hybridized carbon atom. 

Other classical synthetic approaches to 2-furanamine have failed, including the Curtius method and Beckmann rearrangement of 2-benzoylfuran oxime. However, hydrazinolysis of AT-(2-furyl)phthalimide, obtained from phthalimide and 2,5-dimethoxy-2,5-dihy-drofuran, gives 2-furanamine which was not isolated but detected by GLC-MS and H NMR spectroscopy. The latter reveals the absence of imino tautomers (75AP713). The chemistry of 2-dialkylamino-5-phenylfurans is typical of enamines protonation occurs on carbon to produce iminium salts. They are stable to base but afford 5-phenylfuran-2(3//)-one on hydrolysis with dilute acid. 2-Morpholino-5-phenylfuran couples with diazonium salts and affords Diels-Alder adducts with maleic anhydride and IV-phenylmaleimide (73JCS(P1)2523). 

Carbon tetrabromide, AA01 Carbon tetrachloride, AA04 u,-Carbonylhexacarbonyl [u-(5 oxo-2(5H.)-furyl idene)]dicobal t (Co-Co), AS83... 

Even forcing conditions did not cause the anhydro-D-fructose derivative 53 to undergo photochlorination with iV-chlorosuccinimide, but, with sul-furyl chloride-azobis(isobutanonitrile) in refluxing carbon tetrachloride, it gave several products, one of the major being the crystalline a-chloro analog of the bromide 56 (14% isolated).50... 

Reaction with Further Electrophiles of Group IVA (Sl,Ge,Sn). IV-Silylated aziridines can be prepared from ethyleneimine by amination of chlorosilanes in the presence of an HC1 acceptor, by dehydrocondensation with an organosilicon hydride or by cleavage of a silicon—carbon bond in 2-furyl-, 2-thienyl-, benzyl-, or allylsilanes in the presence of an alkali metal catalyst (262—266). N-Silylated aziridines can react with carboxylic anhydrides to give acylated aziridines, eg, A/-acetylaziridine [460-07-1] in high yields (267). At high temperatures, A/-silylaziridines can be dimerized to piperazines (268). Aldehydes can be inserted... 

Synthesis of the dibenzofuran (27) by irradiation of grisa-3, 5 -diene-2, 3 -dione (28) is believed to involve electrocyclic ring opening followed by intramolecular cycloaddition to the ketene and elimination of carbon dioxide, as shown in Scheme 2.24 Analogous photocyclizations are responsible for the photochromism exhibited by heterocyclic fulgides such as ( )-a-3-furyl-ethy idene(isopropylidene)succinic anhydride (29), which on irradiation... 

The cycloaddition of diazomethane to SchifT bases from heterocyclic aldehydes and anilines provides a useful route to heterocyclic substituted triazolines. Unlike olefins bearing heterocyclic substituents, the heterocyclic imines can be obtained readily by reaction of the appropriate aldehyde and amine thus the diazomethane-imine addition has greater scope than the olefin-azide reaction. NMR spectroscopic studies of the orientation of addition are in accord with previously reported mechanistic considerations (see, e.g., Scheme 93).329 In addition to the influence of the N-aryl group, the electron-withdrawing power of the heterocyclic substituent on the Schiff-base carbon also has a substantial effect on imine reactivity, in the order 2-quinolyl 2-, 3-, or 4-pyridyl > phenyl > 2-thienyl as 2-furyl.329... 

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