- KI-catalysed synthesis of 4-methylcatechol dimethylacetate and fragrant compound Calone 1951
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Synthesis of the fragrant compound Calone 1951 from 4-methyl catechol and methyl bromoacetate entails three successive reactions: the Williamson reaction, Dieckmann condensation, and hydrolysis-decarboxylation reaction. In this paper, the synthesis of 4-methylcatechol dimethylacetate (MCDA) via the Williamson reaction by adding KI as catalyst was investigated. It was found that the addition of an appropriate amount of KI can significantly increase the product yield due to generation of methyl iodoacetate via the reaction between KI and methyl bromoacetate. The synthesised MCDA as well as Calone 1951 were first characterised by melting points, HPLC, IR, and NMR analyses. Next, the effect of the key operating factors on MCDA synthesis by the Williamson reaction was investigated and the optimum operating conditions were obtained via a group of orthogonal experiments. The verification experiments demonstrated that, under the optimum operating conditions, the MCDA yield could be increased from 78.5 % to 95.4 % by the addition of an appropriate amount of KI; the corresponding yield of Calone 1951 increased to 68 %.
- Zhang, Ya-Zheng,Yang, Qian,Huang, Shao-Jian,Luo, Zi-Ping,Li, Wen-Ping,Dong, Li-Chun
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- Microwave assisted synthesis of the fragrant compound Calone 1951
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Microwave irradiation has been utilised in a three-step synthetic route to the fragrant compound, 7-methyl-benzo[b][1,4]dioxepin-3-one, commercially known as Calone 1951. The use of a microwave reactor increases the simplicity and efficiency of the overall synthesis. Calone 1951, 7-methyl-benzo[b][1,4]dioxepin-3-one, possesses a strong marine, ozone note with floral nuances and is synthesised via a three-step procedure using microwave irradiation. High yields were obtained, and reaction times reduced to a few minutes, allowing for an efficient and inexpensive synthesis of Calone 1951.
- Drevermann, Britta,Lingham, Anthony,Hügel, Helmut,Marriott, Philip
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- Preparation method of watermelon ketone
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The invention relates to a preparation method of watermelon ketone, which comprises the following steps: by taking 4-methylcatechol and 1,3-dichloroacetone as raw materials and carbonate as a base catalyst, adding a drying agent into a Soxhlet extractor for dehydration, and under the protection of inert gas, assembling a reduced pressure reflux water removal device to prepare a watermelon ketone crude product; carrying out rotary evaporation to recover a solvent, carrying out post-treatment steps of decoloration, concentration and the like, and transferring an obtained solution into a rectification device provided with a glass vacuum rectification column to carry out segmented rectification: in first-stage rectification, evaporating off reaction solvent light components, in second-stage rectification, collecting fractions to obtain a residual raw material 4-methylcatechol and a part of crude product watermelon ketone, and in third-stage rectification, collecting a main fraction watermelon ketone crude product; and recrystallizing the watermelon ketone crude product. According to the preparation method of the watermelon ketone, the yield of the watermelon ketone is improved through the reduced pressure reflux water removal device, the watermelon ketone is purified step by step by combining segmented rectification and recrystallization, the purity of the product reaches 98% or above, the technological process is simplified, and the problem that industrial large-scale production is difficult to achieve through an existing watermelon ketone synthesis technology is solved.
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Paragraph 0059-0143
(2021/08/14)
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- Method for synthesizing watermelon ketone
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The invention belongs to the technical field of perfume compound synthesis. The invention specifically relates to a synthesis method of watermelon ketone. The method comprises the following steps: adding a solvent and a periodate into the reaction vessel at room temperature, stirring uniformly, and then dropwise adding the watermelon ketone precursor alcohol (I) dissolved by the solvent to the reaction vessel to obtain a crude watermelon ketone crude product which is subjected to recrystallization to obtain the watermelon ketone (3 - 7h II) finished product. To the invention, 4 - methylcatechol and 1, 3 -dichloropropanol reaction product 3, 4 - dihydro -7 - methyl - 2H - 1 and 5 - benzoxazole -3 - alcohol (I) are used as starting materials and are subjected to high-iodine reagent oxidation reaction. High yields were obtained. The high-purity citrulline (II) has the advantages of simple process, high product yield, high purity and low cost, and is suitable for industrial production.
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Paragraph 0034-0059
(2021/11/19)
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- A Deoximation Method for Deprotection of Ketones and Aldhydes Using a Graphene-Oxide-Based Co-catalysts System
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The deoximation of a wide range of ketoximes and aldoximes to their corresponding carbonyl compounds with high yields has been achieved using graphene oxide (GO) and sodium nitrite (NaNO2) as highly efficient catalysts and air as the green oxidant under mild conditions. The mechanism of deprotection and recycling use of catalyst were revealed in deep experiment. The carboxylic acid groups on the GO were essential for high catalytic activity. (Figure presented.).
- Tong, Qiaolin,Liu, Yang,Gao, Xuezhi,Fan, Zhanfang,Liu, Tianfu,Li, Bo,Su, Dangsheng,Wang, Qinghe,Cheng, Maosheng
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supporting information
p. 3137 - 3145
(2019/05/01)
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- Watermelon ketone preparation method
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The invention discloses a watermelon ketone preparation method which comprises the following steps: (1) under an alkali condition and in the presence of aids, heating 4-methyl-orthodioxybenzene and alcohol-protected ketalized 1,3-bisubstited acetone to 30-120 DEG C in a solvent, and performing a Williamson ether synthesis reaction so as to generate a corresponding ketal intermittent, wherein reaction materials are fed in the following sequence: firstly, adding the solvent, an alkali and aids, uniformly stirring, heating to a set temperature, slowly dropping 4-methyl-orthodioxybenzene and alcohol-protected ketalized 1,3-bisubstited acetone, and performing a reaction for 2-12 hours after dropping is competed; (2) performing a backflow reaction on the ketal intermittent obtained in the step (1) for a certain time under an acid condition, pouring into water to implement hydrolysis, extracting with ethyl ether, washing an organic phase with a sodium bicarbonate solution, drying sodium sulfate, evaporating off the solvent, and performing recrystallization, thereby obtaining watermelon ketone. The method disclosed by the invention is easy to control, simple to operate, good in environmentprotection, relatively high in yield and beneficial to industrialization.
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- Synthesis of benzodioxepinone analogues via a novel synthetic route with qualitative olfactory evaluation
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Marine odorants represent a minor yet diverse class of substances within the fragrance industry, of which 7-methyl-2H-1,5-benzodioxepin-3(4H)-one (1) is commercially known as Calone 1951, a synthetic first in the area of marine-fragrance chemistry. To determine the extent to which the characteristic marine odor of Calone 1951 corresponds to the substitution at the benzo portion of the molecule, a variety of aromatic substituents were incorporated into the benzodioxepinone structure (Scheme 1, Table 3). In light of the difficulty experienced in applying patented literature to deriving the analogues 12-18, particularly those with electron-withdrawing substituents, an alternative synthetic scheme was implemented for the construction of all analogues in favorable yields (Scheme 4, Table 3). Formation of the hydroxy-protected dihalo alkylating agent 24 via epoxide cleavage of epichlorohydrin (Scheme 3) allowed etherification favoring dihalo displacement and subsequent intramolecular ring closure (-→26a-g). THP Deprotection followed by oxidation of the alcohols 27a-g to the ketones 12-18 provided a general pathway to the benzodioxepinone products. The influence of the substituent nature on odor activity revealed a diverse scope of olfactory character (Table 4).
- Drevermann, Britta,Lingham, Anthony R.,Huegel, Helmut M.,Marriott, Philip J.
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p. 1006 - 1027
(2008/02/04)
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- Structure-activity relationship in the domain of odorants having marine notes
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We synthesized or re-synthesized a large series of 2H-1,5-benzodioxepin- 3(4H)-ones 9 (Scheme 1), 4,5-dihydro-1-benzoxepin-3(2H)-ones 10 (Schemes 3 and 4) and 5,6,8,9-tetrahydro-7H-benzocyclohepten-7-ones 11 (Schemes 5 and 6), since the lead compound for the olfactory note of perfumes based on marine accords is a well-known benzodioxepinone named Calone 1951 (9b). We meticulously described the odor profile of each synthesized compound and discussed relevant structure-odor relationships (Tables 1-3). In particular, we revealed a correlation between the conformation of the seven-membered ring and the activities of these compounds (Table 4 and Fig. 3). We also clarified the effect of the position and the size of the alkyl substituent at the aromatic ring.
- Gaudin, Jean-Marc,Nikolaenko, Olga,De Saint Laumer, Jean-Yves,Winter, Beat,Blanc, Pierre-Alain
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p. 1245 - 1265
(2008/02/07)
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- Method for producing seven-membered diether compounds and intermediates thereof
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The invention provides a method for preparing 3,4-dihydro(2H)-1,5-benzodioxepin-3-ones represented by the formula (3): wherein R1, R2, R3 and R4 respectively represent, independently, a hydrogen atom an alkyl group or an alkenyl group, and R1, R2, R3 and R4 as a whole do not comprise more than 10 carbon atoms and that, when the two adjacent groups respectively comprise an alkyl group or an alkenyl group, they may be combined together to form a carbon ring; by reacting either a compound represented by the formula (1a) and/or (1b): wherein X represent a halogen atom; and R1, R2, R3 and R4 are as defined above; or catechols represented by the formula (5): wherein R1, R2, R3 and R4 are as defined above; with 1,3-dihaloacetones in the presence of sodium carbonate, through the removal of hydrogen halide.
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