There is provided an α-carbonyl alkenyl ester and a preparation method therefor, and the α-carbonyl alkenyl ester is further used to react with a primary or secondary amine to prepare an amide. The two reactions are combined to develop an amide bond and peptide bond formation method that directly use carboxylic acids and amines as starting materials and allenones as a condensing reagent. The α-carbonyl alkenyl ester corresponding to an α-amino acid serves as a peptide synthesis building block and is used in solid phase peptide synthesis. The method is carried out under mild reaction conditions, simple to operate, and has a high yield. Compared with existing amide bond condensation reagents, the allenones have the advantages of being simple to prepare, having good stability, a low molecular weight, not racemizing when activating α-chiral carboxylic acids, and is a novel amide bond and peptide bond condensing reagent.

There is provided an α-carbonyl alkenyl ester and a preparation method therefor, and the α-carbonyl alkenyl ester is further used to react with a primary or secondary amine to prepare an amide. The two reactions are combined to develop an amide bond and peptide bond formation method that directly use carboxylic acids and amines as starting materials and allenones as a condensing reagent. The α-carbonyl alkenyl ester corresponding to an α-amino acid serves as a peptide synthesis building block and is used in solid phase peptide synthesis. The method is carried out under mild reaction conditions, simple to operate, and has a high yield. Compared with existing amide bond condensation reagents, the allenones have the advantages of being simple to prepare, having good stability, a low molecular weight, not racemizing when activating α-chiral carboxylic acids, and is a novel amide bond and peptide bond condensing reagent.

There is provided an α-carbonyl alkenyl ester and a preparation method therefor, and the α-carbonyl alkenyl ester is further used to react with a primary or secondary amine to prepare an amide. The two reactions are combined to develop an amide bond and peptide bond formation method that directly use carboxylic acids and amines as starting materials and allenones as a condensing reagent. The α-carbonyl alkenyl ester corresponding to an α-amino acid serves as a peptide synthesis building block and is used in solid phase peptide synthesis. The method is carried out under mild reaction conditions, simple to operate, and has a high yield. Compared with existing amide bond condensation reagents, the allenones have the advantages of being simple to prepare, having good stability, a low molecular weight, not racemizing when activating α-chiral carboxylic acids, and is a novel amide bond and peptide bond condensing reagent.

The present invention generally relates to novel synthetic methods, systems, kits, salts, and precursors useful in medical imaging. In some embodiments, the present invention provides compositions comprising an imaging agent precursor, which may be formed using the synthetic methods described herein. An imaging agent may be converted to an imaging agent using the methods described herein. In some cases, the imaging agent is enriched in .sup.18F. In some cases, an imaging agent including salt forms (e.g., ascorbate salt) may be used to image an area of interest in a subject, including, but not limited to, the heart, cardiovascular system, cardiac vessels, brain, and other organs.

The present invention generally relates to novel synthetic methods, systems, kits, salts, and precursors useful in medical imaging. In some embodiments, the present invention provides compositions comprising an imaging agent precursor, which may be formed using the synthetic methods described herein. An imaging agent may be converted to an imaging agent using the methods described herein. In some cases, the imaging agent is enriched in .sup.18F. In some cases, an imaging agent including salt forms (e.g., ascorbate salt) may be used to image an area of interest in a subject, including, but not limited to, the heart, cardiovascular system, cardiac vessels, brain, and other organs.

The present invention generally relates to novel synthetic methods, systems, kits, salts, and precursors useful in medical imaging. In some embodiments, the present invention provides compositions comprising an imaging agent precursor, which may be formed using the synthetic methods described herein. An imaging agent may be converted to an imaging agent using the methods described herein. In some cases, the imaging agent is enriched in .sup.18F. In some cases, an imaging agent including salt forms (e.g., ascorbate salt) may be used to image an area of interest in a subject, including, but not limited to, the heart, cardiovascular system, cardiac vessels, brain, and other organs.

The present invention generally relates to novel synthetic methods, systems, kits, salts, and precursors useful in medical imaging. In some embodiments, the present invention provides compositions comprising an imaging agent precursor, which may be formed using the synthetic methods described herein. An imaging agent may be converted to an imaging agent using the methods described herein. In some cases, the imaging agent is enriched in .sup.18F. In some cases, an imaging agent including salt forms (e.g., ascorbate salt) may be used to image an area of interest in a subject, including, but not limited to, the heart, cardiovascular system, cardiac vessels, brain, and other organs.

The disclosure features novel lipids and compositions involving the same. Nanoparticle compositions include a novel lipid as well as additional lipids such as phospholipids, structural lipids, and PEG lipids. Nanoparticle compositions further including therapeutic and/or prophylactics such as RNA are useful in the delivery of therapeutic and/or prophylactics to mammalian cells or organs to, for example, regulate polypeptide, protein, or gene expression.

The disclosure features novel lipids and compositions involving the same. Nanoparticle compositions include a novel lipid as well as additional lipids such as phospholipids, structural lipids, and PEG lipids. Nanoparticle compositions further including therapeutic and/or prophylactics such as RNA are useful in the delivery of therapeutic and/or prophylactics to mammalian cells or organs to, for example, regulate polypeptide, protein, or gene expression.

The invention provides a compound of formula I and stereoisomers, tautomers, or pharmaceutically acceptable salts thereof, and with the substituents and structural features described herein. Also described are pharmaceutical compositions and medicaments that include the formula I compounds, as well as methods of using such as therapeutic agents for the treatment of pain-related disorders and diseases and in combination with other therapeutic agents.

##STR00001##