Über eine neue Methode zur synthetischen Darstellung der Isochinolinbasen

Abstract

Gef. n 59.96, s 4.60, s 12.91. Auch mit 1 xol. Phenyl-Go-cyanat gibt die Base eine Verbindung, wenn man ihre benzolische LBsuog mit einer ebensolchen des gleichen Gewichts (also eines groBen Uberschusses) von Isocyanat vermischt. Dann entsteht eine sich rnsch vermehrende Ausscheidung von blaBgelblichen Aggregaten feiuer Niidelchen, die abgesaugt und eiumal aus Athyl-, einmal am Methylalkohol nmkrystallisiert, weiBe Rosetten und Krusten bildet, die bei 1880 unter Zentetzung schmelzen. 0.1881 g Sbst.: 0.5310 g Con, 0.1083 g H90. -0.1538 g Sbst.: 12.77 ccm N (23O, 762.3 mm). CrlH?oNsO,C~H~NO. Ber. C 77.24, H 5.75, N 9.65.Gef. s 77.08, s 6.34, s 9.27. Versuche, die Base zu acetylieron oder zu m e t h y l i c r e n , scblugen fehl; ebenso blieb H y d r o x y l a m i n ohne jede Einwirkung.Wiihrend das isomere Chinonmonimid durch Einwirkung von oascentem Wasserstoff leicht entflrbt, dann aber durch den Sanerstoff der Luft alsbald wieder regeneriert wird, verschwindet die gelbe Farbe einer alkoholischen Losung der Phenoxnzinbase erst nach langerern Kochen mit Zink oder Zinn und Saure, ist dann aber durch Oxydation nicht wieder herstellbar. Es tritt also viillige Zersetzung der Base ein, als deren Endprodukt in allen Fallen p -T o l u i d i n auftrat, wahrend es trotz zahlreicher Versuche nicht gelang, ein Zwischenprodukt der Reduktion in wesentlicher Menge zu fassen.C h a r l o t t e n b u r g , Laboratorium fur organische Chemie der Kiinigl. Technischen Hochschule.

Pyridoimidazoles, Histidine-Specific Reaction Products

“…We suggest that the aldehyde group of pyruvic aldehyde can react with the amine residue of histamine (I), yielding a Schiff base which forms II by cyclization, analogous to the isoquinoline pathway described by Pictet (2). Subsequent dehydration forms the pyrido-imidazole III.…”

Comprehensive Strategies for the Synthesis of Isoquinolines: Progress Since 2008

“…[24] Later on, people have started working on metal free conditions and came with the altered version of Bischler, namely, Fritsch and Pomeranz in 1890, [25] Pictet in 1910. [26][27] After that people haven't focused much on the synthesis of isoquinoline using metal free conditions. The reason being that, the metal catalysis came into moonlight in the middle of 20 th century and people were more interested towards metal catalysis due to the features possessed by metal orbitals.…”

“…for the synthesis of isoquinoline derivatives. Traditional approaches towards isoquinoline derivatives typically including the well-established Bischler-Napieralski, [24] Pomeranz-Fritsch, [25] Pictet-Gams [26] and Pictet-Spengler [27] reactions, often suffer due to limitations such as using a highly preactivated substrates or harsh reaction conditions and poor functional group tolerance. Research groups of Ackermann, [28] Fagnou, [29] Glorius, [30] Larock, [31] and Chiba [32] have made progresses in addressing these issues by developing more facile protocols with the following advantages like, without the use of any preactivated substrates, diverse substrate scope and better functional group tolerance.…”

“…But, most of the people assumed that Bischler and Napieralski developed the first protocol for the synthesis of isoquinoline in 1893 [24] . Later on, people have started working on metal free conditions and came with the altered version of Bischler, namely, Fritsch and Pomeranz in 1890, [25] Pictet in 1910 [26–27] . After that people haven't focused much on the synthesis of isoquinoline using metal free conditions.…”

Advances in the Preparation of Fluorinated Isoquinolines: A Decade of Progress

“…By 1893, several syntheses of isoquinolinoid compounds were published by Pomeranz, Fritsch, Bischler, and Napieralski, reactions which bear their names [2][3][4]. Early in the 20th century, Pictet, Gams, and Spengler developed slightly different approaches to prepare isoquinoline derivatives [5,6].…”