Spring @Transactional not working In standalone application

I have a standalone application in which I am trying to populate a database. My application config looks like:

@Configuration
@EnableTransactionManagement
@PropertySource(value = { "classpath:classpath property file" })
@ComponentScan(basePackages = { my packages to scan })
public class PersistenceJPAConfig {    

    @Bean
    public EntityManagerFactory entityManagerFactoryBean() {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(dataSource());
        em.setPackagesToScan(new String[] { packages to scan});

        JpaVendorAdapter vendorAdapter = jpaVendorAdapter();
        em.setJpaVendorAdapter(vendorAdapter);
        em.setJpaProperties(additionalProperties());
        em.afterPropertiesSet();

        return em.getObject();
    }

    @Bean
    public JpaVendorAdapter jpaVendorAdapter() {
        HibernateJpaVendorAdapter jpaVendorAdapter = new HibernateJpaVendorAdapter();
        jpaVendorAdapter.setDatabase(Database.ORACLE);
        return jpaVendorAdapter;
    }

    @Bean
    public static PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
        return new PropertySourcesPlaceholderConfigurer();
    }

    @Bean
    public DataSource dataSource() {
        DriverManagerDataSource dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("oracle.jdbc.driver.OracleDriver");
        dataSource.setUrl(url);
        dataSource.setUsername(dbUser);
        dataSource.setPassword(dbPassword);
        return dataSource;
    }

    @Bean
    public PlatformTransactionManager transactionManager() {
        JpaTransactionManager transactionManager = new JpaTransactionManager();
        transactionManager.setEntityManagerFactory(entityManagerFactoryBean());

        return transactionManager;
    }

    @Bean
    public PersistenceExceptionTranslationPostProcessor exceptionTranslation() {
        return new PersistenceExceptionTranslationPostProcessor();
    }

    Properties additionalProperties() {
        return new Properties() {
            { // Hibernate Specific:
                setProperty("hibernate.hbm2ddl.auto", "validate");
                setProperty("hibernate.dialect", "org.hibernate.dialect.Oracle10gDialect");
            }
        };
    }
}

However when I am trying to persist something in database, the annotation is failing with error: Exception in thread "main" javax.persistence.TransactionRequiredException: No transactional EntityManager available

In the resulting error stack, I don't see the transactional advice being applied.

The file that contains transactional annotation is something like this:

import org.springframework.transaction.annotation.Transactional;

@Service
public class MyService {

    @Autowired
    private MyDao myDao;

    @Transactional
    public void save(MyEntity e) {
        myDao.save(e);
    }
}

The MyDao class is something like this:

@Repository
public class MyDao {
    @PersistenceContext
    private EntityManager entityManager;

    public void save(MyEntity e) {
        entityManager.persist(e);
    }

}

I am calling the function from my Main method as follows:

public static void main(String[] args) {

    try (AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext()) {
        ctx.scan(CONFIG_PACKAGE);
        ctx.refresh();
        myService = ctx.getBean(MyService.class);
        Thread.sleep(10 * 1000);
        myService.save(entity);
        ...
}

Can anyone please help me with this, i.e. what I might be doing wrong? Thanks for your help