37864-64-5

Upstream product

• 616-42-2 dimethylsulfite 
• 643-79-8 o-phthalic dicarboxaldehyde 
• 67-56-1 methanol 
• 85-44-9 phthalic anhydride 
• 612-14-6 phthalyl alcohol 
• 13209-15-9 1,2-bis(dibromomethyl)benzene 
• 149-73-5 trimethyl orthoformate 

Downstream Products

• 643-79-8 o-phthalic dicarboxaldehyde 

Relevant academic research and scientific papers

New methods to synthesize phthalaldehyde and its diacetals

A new synthesis of phthalaldehyde that avoided formation of HBr involved treatment of 1,2-bis(dibromomethyl)benzene with trimethyl orthoformate (1: 6, 90 °C, 10 mol.% ZnCl2) to obtain acyclic diacetal without admixture of cyclic one (1,3-dimethoxy-1,3-dihydrobenzo-[c]furan) followed by hydrolysis to give the target dialdehyde. Phthalaldehyde reacted with CH(OMe)3 in the presence of trifluoroacetic acid to yield exclusively cyclic diacetal. Acyclic diacetal was phosphorylated by treatment with secondary chlorophosphines and by the reaction with PCl3 followed by treatment with PIII acid ester.

Synthesis of Phthalic Aldehyde and Its Diacetals

Acyclic phthalaldehyde diacetal without cyclic 1,3-dihydro-1,3-dimethoxybenzo[c]furan impurity has been obtained via the reaction of 1,2-bis(dibromomethyl)benzene with trimethyl orthoformate (1:6) at 90°C in the presence of 10 mol% of ZnCl2. Hydrolysis of phthalaldehyde diacetal has led to the formation of phthalaldehyde without HBr evolution. The reaction of phthalaldehyde with trimethyl orthoformate in the presence of trifluoroacetic acid has proceeded abnormally, with the formation of the cyclic diacetal. The acyclic diacetal has been phosphorylated by chlorophosphines and the action of PCl3 and a P(III) acid ester in sequence.

METHOD FOR PRODUCING ALKOXYLATED 2,5-DIHYDROFURAN BUT-2-ENE DERIVATIVES OR TETRA-1,1,4,4-ALKOXYLATED BUT-2-ENE DERIVATIVES

The invention relates to a method for producing 2,5-dihydrofuran derivatives that are substituted in position 3 or 4, which carry a respective C1 to C6 alkoxy group (DHF alkoxy derivates I) in position 2 or position 5, or in both positions, or for producing 1,1,4,4-tetraalkoxy but-2-ene derivatives that are substituted in position 3 or 4, from 2-butene-1,4-diol derivatives of general formula (I), in which the groups R1 and R2 independently of one another represent hydrogen, C1 to C6 alkyl, C6 to C12 aryl or C5 to C12 cycloalkene or R1 and R2 together with the double bond, to which they are linked, form a C6 to C12 aryl group or a mono- or polyunsaturated C5 to C12 cycloalkyl group, or from a mixture of said 2-butene-1,4-diol derivatives and 2,5-dihydrofuran derivatives that are substituted in position 3 or 4 and carry a C1 to C6 alkoxy group in position 2 or 5, by electrochemical oxidation in the presence of a C1 to C6 monoalkyl alcohol.

METHOD FOR PRODUCING ALKOXYLATED 2,5-DIHYDROFURAN OR TETRA-1,1,4,4-ALKOXYLATED BUT-2-ENE DERIVATIVES

The invention relates to a method for producing 2,5-dihydrofuran derivatives, which are substituted in the 3-position or 4-position and which support a C1-C6 alkoxy radical in the 2-position or 5-position or in both positions or for producing 1,1,4,4-tetraalkoxy-but-2-ene derivatives (DHF-alkoxy derivatives I), which are substituted in the 3-position or 4-position, from 2,5-dihydrofuran derivatives, which are substituted in the 3-position or 4-position, or C1-C6-alkoxy derivatives of 2,5-dihydrofuran derivatives, which are substituted in the 3-position or 4-position and which have a lower number of alkoxy radials than the DHF alkoxy derivatives I (DHF-alkoxy derivatives II). To this end, a compound or mixtures of compounds that are selected from the group consisting of the 2,5-dihydrofuran derivatives, which are substituted in the 3-position or 4-position, and DHF-alkoxy derivatives II are electrochemically oxidized in the presence of a C1 to C6 alkyl alcohol.

Efficient acetalisation of aldehydes catalyzed by titanium tetrachloride in a basic medium

The acetalisation of aliphatic and aromatic aldehydes is achieved in a basic medium by using catalytic amount of Ti(IV) chloride in MeOH in the presence of NH3 or Et3N. The present protocol shows many advantages over the well known base or acid catalysis: in fact, in contrast to base-promoted acetalisation, aldehydes with electron-rich carbonyl groups react easily, enolizable aldehydes do not undergo aldol condensation and, in contrast to acid-catalysis, migration of the double bond does not occur in the preparation of α,β-unsaturated acetals.

1-Methoxyisobenzofuran from Base-Induced and Acid-Catalyzed Reactions of 1,3-Dihydro-1,3-dimethoxyisobenzofuran

The title bis acetal (1) has been used in both acid-catalyzed and strong base induced procedures to generate 1-methoxyisobenzofuran (2).The acid-catalyzed reaction is not synthetically useful, since it requires forcing conditions and gives cycloadduct only with very reactive dienophiles (e.g., maleic anhydride).However, the LiNR2-induced 1,4-elimination reaction of 1 yields isolable solutions of 2.This process is strongly solvent-dependent, being more rapid in THF than in diethyl ether, and very slow in hexane.The elimination exhibits syn selectivity in ether solvent, allowing the recovery of unreacted 1 enriched in the cis isomer.However, cis 1 also undergoes base-induced elimination to form 2, showing that an anti elimination pathway, although not favored, is energetically accessible.The utility of the base-induced method was demonstrated by the formation of the 3-lithiated derivative of 2, which was in turn converted to 1-methoxy-3-(trimethylsilyl)isobenzofuran.This derivative gave cycloadducts upon treatment with the dienophiles N-methylmaleimide and benzyne, the latter generated by dehydrohalogenation of bromobenzene.

THE INTRAMOLECULAR CANNIZZARO REACTION OF PHTHALALDEHYDE

Phthalaldehyde undergoes an intramolesular Cannizzaro reaction in aqueous base to produce the o-hydroxymethylbenzoate ion.The kinetics of the reaction have been measured over a range of sodium hydroxide concentration at 40 degC.The reaction is considerably slower than of the analogous reaction of phenylglyoxal since it proceeds exclusively via the cyclic hydrate dianion which must undergo a very unfavorable ring opening before internal hydride transfer can occur.