Synthesis of tricarbonylated propargylamine and conversion to 2,5-disubstituted oxazole-4-carboxylates

• Kento Iwai,
• Akari Hikasa,
• Kotaro Yoshioka,
• Shinki Tani,
• Kazuto Umezu and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2024, 20, 2827–2833, doi:10.3762/bjoc.20.238

• reacts with butyllithium, ring closure occurs between the ethynyl and carbamoyl groups, yielding 2,5-disubstituted oxazole-4-carboxylates. This cyclization also occurs when the propargylamine is heated with ammonium acetate, resulting in double activation. Keywords: acid amide; diethyl mesoxalate; N

• anhydride, the intermediately formed hemiacetal underwent acetylation, leading to N,O-acetals 1. In this method, an acid amide can be used as an amine masked with an acyl group. Subsequent elimination of acetic acid occurred to afford 2 in situ upon treatment with a base, enabling nucleophilic addition with

• various nucleophiles. This is because the imino carbon atom of 2 is also highly electrophilic, similar to DEMO [23][24][25]. This method offers an advantage over conventional methods as the N-acyl group can be modified by altering the acid amide. In this study, lithium acetylides were employed as

Ugi bisamides based on pyrrolyl-β-chlorovinylaldehyde and their unusual transformations

• Alexander V. Tsygankov,
• Vladyslav O. Vereshchak,
• Tetiana O. Savluk,
• Serhiy M. Desenko,
• Valeriia V. Ananieva,
• Oleksandr V. Buravov,
• Yana I. Sakhno,
• Svitlana V. Shishkina and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2024, 20, 1773–1784, doi:10.3762/bjoc.20.156

• ) and p-anisidine (2a), the product that precipitated first from the reaction mixture was 2-oxo-4-(1H-pyrrol-3-yl)but-3-enoic acid amide 10b (Scheme 4; Table 1, footnote b). Pure Ugi bisamide 6a could only be obtained when the reaction was carried out in MeCN or EtOH. The same was observed in the case

(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• ]. The ability of 1,5-BCHeps to act as bioisosteres of meta-benzenes was also studied by Anderson and co-workers. They reported the comparison of fatty acid amide hydrolase inhibitor URB597 with its 1,5-BCHep isostere 146 (Figure 21) [27]. They found that while replacement of one of the meta-benzenes

Synthesis of (−)-halichonic acid and (−)-halichonic acid B

• Keith P. Reber and
• Emma L. Niner

Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174

• amine derivatives (e.g., hydrochloride salt, mandelic acid salt, phthalimide, ketopinic acid amide, salicylaldehyde imine, p-toluenesulfonamide, acetamide, etc.), all attempts to separate the resulting isomers (which were oils) were similarly unsuccessful. Seeking an alternative to column chromatography

A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine

• Raphael Bereiter,
• Marco Oberlechner and
• Ronald Micura

Beilstein J. Org. Chem. 2022, 18, 1617–1624, doi:10.3762/bjoc.18.172

• , glycogen synthase kinase 3 (GSK-3), leucine-rich repeat kinase 2 (LRRK2), tyrosine phosphorylation-regulated kinase-1A (DYRK1A) and CDC2-like kinase 1 (CLK1), and fatty acid amide hydrolase (FAAH) [4]). Similar properties were ascertained for 1-deazapurine derivatives (imidazo[4,5-b]pyridines) and

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• aniline 94 in three steps (Scheme 16). Subsequent deprotection and condensation with dimethyl mesoxalate (90b) gave imidazolidine 95. With compound 95 at hands, five further steps gave (−)-aplaminal (96) in a good overall yield of 19%. Cladoniamide G The unsymmetrical mesoxalic acid amide 102 was used by

¹⁹F NMR as a tool in chemical biology

• Diana Gimenez,
• Aoife Phelan,
• Cormac D. Murphy and
• Steven L. Cobb

Beilstein J. Org. Chem. 2021, 17, 293–318, doi:10.3762/bjoc.17.28

• further expanded the applications of n-FABS into the screening and direct IC50 measurement of bioactive substrates within intact living cells [45]. By studying mammalian cells expressing the membrane protein fatty acid amide hydrolase (FAAH), they showed that it is possible to screen and identify target

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• efficacy. We also examined an alternative approach to β-ketoenamides by the addition of carboxylic acid amides to alkynones. This approach can potentially lead to products that are formally derived from unsymmetrically substituted 1,3-dicarbonyl compounds. The best result was obtained with picolinic acid

• amide and but-3-yn-2-one (as an equivalent of 3-oxobutanal) using methanol as solvent in a sealed tube [29]. Disappointingly, the maximum yield for compound 3h was only 22%. Many attempts to improve this result – including gold catalysis [30] – either led to lower yields or no conversion at all [31]. We

Catalytic asymmetric synthesis of biologically important 3-hydroxyoxindoles: an update

• Bin Yu,
• Hui Xing,
• De-Quan Yu and
• Hong-Min Liu

Beilstein J. Org. Chem. 2016, 12, 1000–1039, doi:10.3762/bjoc.12.98

• proline and its derivatives [31]. Recently, Hoveyda and co-workers designed a novel amino acid amide catalyst (cat. 4) for the asymmetric addition of unsaturated organoboranes to carbonyls and imines, producing the corresponding enantiomerically pure alcohols and amines in excellent yields [32]. As shown

Multicomponent reactions in nucleoside chemistry

• Mariola Koszytkowska-Stawińska and
• Włodzimierz Buchowicz

Beilstein J. Org. Chem. 2014, 10, 1706–1732, doi:10.3762/bjoc.10.179

• substrate afforded nucleosides 30 bearing a N-acyl α-amino acid amide moiety at the uracil C-5 carbon atom (Scheme 14) [79]. The variant of the reaction with trimethylsilyl azide (TMS-N3) in place of the carboxylic acid gave the tetrazole-substituted nucleosides 31 [79]. Products 30 and 31 were obtained as

Isocyanide-based multicomponent reactions towards cyclic constrained peptidomimetics

• Gijs Koopmanschap,
• Eelco Ruijter and
• Romano V.A. Orru

Beilstein J. Org. Chem. 2014, 10, 544–598, doi:10.3762/bjoc.10.50

• ], the CB1 receptor of cannabinoid and fatty acid amide hydrolase [114][118][119][120][121]. In this context, Hulme and co-workers described a Passerini multicomponent approach towards cis-constrained norstatine mimics, a class of HIV-1 protease inhibitors with a tetrazole core (Scheme 45) [122]. They

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• ) iodide, copper(I) triflate or tetrakis(acetonitrile)copper(I) hexafluorophosphate can be used in the presence of a nitrogen base with acetonitrile as co-solvent. This reaction is applicable to a great variety of substrates with manifold functional groups, e.g. free hydroxy, ester, carboxylic acid, amide

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• , derivatives containing carbonyl groups (ester, acid, amide and ketone) and heteroatoms, such as nitrogen and phosphorous, have been obtained. In 1993, Shinkai et al. [29] reported the synthesis of the first ethyl ester derivative 12a. In the belief that the alkali-metal template effect would lead

A new phenylethyl alkyl amide from the Ambrostoma quadriimpressum Motschulsky

• Guolei Zhao,
• Chao Yang,
• Bing Li and
• Wujiong Xia

Beilstein J. Org. Chem. 2011, 7, 1342–1346, doi:10.3762/bjoc.7.158

• chain was accomplished by the selective protection of the hydroxy groups and two-time implementation of the Wittig olefination reaction. Keywords: asymmetric synthesis; beetle; fatty acid amide; isolation; Introduction The leaf beetle Ambrostoma quadriimpressum Motschulsky (Coleoptera: Chrysomelidae

• . Fraction 4 was further separated into seven fractions on a silica gel column (PE/AcOEt 10:1→1:1). GC–MS analysis showed that fractions 4-4 and 4-5 included derivatives of a fatty acid amide. Fraction 4-5 was further purified by crystallization in diethyl ether to yield compound 1 (3 mg) as a white solid

Thermal rearrangement of tert-butylsulfinamide

• Veera Reddy Arava,
• Laxminarasimhulu Gorentla and
• Pramod Kumar Dubey

Beilstein J. Org. Chem. 2011, 7, 9–12, doi:10.3762/bjoc.7.2

• room temperature and in chlorinated solvents. Experimental See Supporting Information File 1 for full experimental data. tert-Butylsulfinamide. N-(tert-butylthio)-tert-butylsulfonamide. ORTEP diagram of 3. Synthesis of acid amide. Chemical synthesis of 3. Synthesis of tert-butylsulfanyl chloride

Stereoselective synthesis of (2S,3S,4Z)-4-fluoro- 1,3-dihydroxy- 2-(octadecanoylamino)octadec- 4-ene, [(Z)-4-fluoroceramide], and its phase behavior at the air/water interface

• Gergana S. Nikolova and
• Günter Haufe

Beilstein J. Org. Chem. 2008, 4, No. 12, doi:10.3762/bjoc.4.12

• fatty acid amide functions. Results In a short synthetic route (2S,3S)-4-fluorosphingosine and 4-fluoroceramide, the fluorinated analogues of the natural products, D-erythro-sphingosine and ceramide, have been prepared. The key step of the synthetic sequence is an asymmetric aldol reaction of (Z)-2

• water permeability barrier consisting of a highly organized multilaminar lipid matrix of free fatty acids, cholesterol and ceramides containing additional hydroxyl groups in the sphingosin part and longer fatty acid amide functions [23]. The function of the additional free OH group seems to be the