Cryptophycin unit B analogues

• Thomas Schachtsiek,
• Jona Voss,
• Maren Hamsen,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2025, 21, 526–532, doi:10.3762/bjoc.21.40

• acidolysis was followed by macrolactamisation to obtain diol 24, albeit in poor yield of 11%. LC–MS analyses revealed that the low yield cannot be attributed to either incomplete acidolysis or incomplete conversion of the deprotected seco-cryptophycin during macrolactamisation. Rather, LC–MS analyses

A novel methodology for the efficient synthesis of 3-monohalooxindoles by acidolysis of 3-phosphate-substituted oxindoles with haloid acids

• Li Liu,
• Yue Li,
• Tiao Huang,
• Dulin Kong and
• Mingshu Wu

Beilstein J. Org. Chem. 2021, 17, 2321–2328, doi:10.3762/bjoc.17.150

• University, Haikou 571199, Hainan Province, P. R. China 10.3762/bjoc.17.150 Abstract A novel method for the synthesis of 3-monohalooxindoles by acidolysis of isatin-derived 3-phosphate-substituted oxindoles with haloid acids was developed. This synthetic strategy involved the preparation of 3-phosphate

• -substituted oxindole intermediates and SN1 reactions with haloid acids. This new procedure features mild reaction conditions, simple operation, good yield, readily available and inexpensive starting materials, and gram-scalability. Keywords: acidolysis; haloid acids; isatin; 3-monohalooxindole; 3-phosphate

• yield (92%, Table 1, entry 13). However, further increasing the reaction temperature to 60 °C led to a sharp decrease of the yield (Table 1, entry 14). Therefore, 50 °C was set as the most suitable reaction temperature. Furthermore, we evaluated the effect of the reaction time on the acidolysis reaction

In search of visible-light photoresponsive peptide nucleic acids (PNAs) for reversible control of DNA hybridization

• Lei Zhang,
• Greta Linden and
• Olalla Vázquez

Beilstein J. Org. Chem. 2019, 15, 2500–2508, doi:10.3762/bjoc.15.243

• compatible with the standard TFA/m-cresol/H2O (90:5:5) acidolysis yielding the photoswitchable PNA conjugates. These and all further studied PNAs in this work (Table 2) were purified by reversed-phase (RP) HPLC and fully characterized. Analogous compounds lacking the photoswitch were used as controls. First

Design, synthesis and structure of novel G-2 melamine-based dendrimers incorporating 4-(n-octyloxy)aniline as a peripheral unit

• Cristina Morar,
• Pedro Lameiras,
• Attila Bende,
• Gabriel Katona,
• Emese Gál and
• Mircea Darabantu

Beilstein J. Org. Chem. 2018, 14, 1704–1722, doi:10.3762/bjoc.14.145

• (paracetamol) and subsequent reduction of the nitro group [23][25][27][29] or acidolysis of the amide sequence [24][26][28]. Our expertise on the use of paracetamol under Williamson etherification conditions [42] (Scheme 1, convergent route) did not impel us in the direction of preliminary 4-(n-octyloxy

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides

• Valentin A. Rassadin,
• Mirko Scholz,
• Anastasiia A. Klochkova,
• Armin de Meijere and
• Victor V. Sokolov

Beilstein J. Org. Chem. 2017, 13, 1932–1939, doi:10.3762/bjoc.13.187

• can be considered as a viable approach to five- and six-membered benzannelated sultams. The 4-methoxybenzyl group is a suitable protective group for the sultam synthesis since it is stable under the reaction conditions and can be easily removed by acidolysis with trifluoroacetic acid. Structure of

Synthesis and biological evaluation of a novel MUC1 glycopeptide conjugate vaccine candidate comprising a 4’-deoxy-4’-fluoro-Thomsen–Friedenreich epitope

• Manuel Johannes,
• Maximilian Reindl,
• Bastian Gerlitzki,
• Edgar Schmitt and
• Anja Hoffmann-Röder

Beilstein J. Org. Chem. 2015, 11, 155–161, doi:10.3762/bjoc.11.15

• -threonine building block 7a [49] affording the desired ß-configured 4’-deoxy-4’-fluorodisaccharide 8 in 80% yield. Subsequent two-step protecting group manipulation and acidolysis of the tert-butyl ester finally provided the orthogonally protected 4’-fluoro-TF-SPPS-building block 11 in 85% yield over three

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• and in some cases, the repetitive TFA acidolysis for Boc deprotection could have an impact on sensitive peptide bonds and acid-catalyzed side reactions [39]. And, since it is no orthogonal strategy, the Bn removal always leads to Boc deprotection. A tremendous diversity of side-chain protection groups

• , Aa: amino acid. Fmoc/t-Bu (A) and Boc/Bn (B) protecting-group strategies applied in SPPS. (A) The Fmoc-group is removed by β-elimation through piperidine and t-Bu is released by acidolysis with TFA. (B) Cleavage of protecting groups with TFA and HF occurs by acidolysis. Removal reactions of the

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• of different starting oxazaphospholidine borane complexes 7 from (−)-ephedrine or (+)-ephedrine [38] or by starting from the same oxazaphospholidine borane adduct 7 and then changing the order of addition of the organolithium reagents (Scheme 2). Acidolysis with HCl of compounds 8a results in the

A novel family of (1-aminoalkyl)(trifluoromethyl)- and -(difluoromethyl)phosphinic acids – analogues of α-amino acids

• Natalia V. Pavlenko,
• Tatiana I. Oos,
• Yurii L. Yagupolskii,
• Igor I. Gerus,
• Uwe Doeller and
• Lothar Willms

Beilstein J. Org. Chem. 2014, 10, 722–731, doi:10.3762/bjoc.10.66

• 24 in satisfactory yields (Scheme 5). Attempts to convert ester 23 to the free acid failed. Removal of the ester group from 23 by acidolysis with HCl or HI was accompanied by cleavage of the P–C bond to give only (trifluoromethyl)phosphonic acid (10) after an ion-exchange chromatography. Attempts to

• [33], readily gave adducts 27 and 28, which were decarboxylated under acidolysis to afford the phosphinic acid analogues of valine 14d and 20d (Scheme 7). The hydrophosphinylation of substrates with activated C=C double bonds The high reactivity of (trifluoromethyl)phosphinic acid (1) with C=N double

• %). Products 35 and 36 were separated by chromatography and characterized. Ester 36 was obtained as a mixture of two diastereoisomers, which are clearly seen by 1H- and 19F NMR. This ester was then readily converted by acidolysis into the phosphinic acid analogue 37, of N-acetylalanine, which was isolated in

The arene–alkene photocycloaddition

• Ursula Streit and
• Christian G. Bochet

Beilstein J. Org. Chem. 2011, 7, 525–542, doi:10.3762/bjoc.7.61

• ). Acidolysis of meta photocycloaddition compounds has been studied by Gilbert [55]. He observed that the cyclopropane ring opens upon protonation of the double bond. If the meta photocycloaddition product contains a substituent at position 1, ring opening affords bicyclo[3.2.1]octane derivatives, whilst if no